fix: confirm email changes and enforce clean backend build

2026-05-07 14:39:22 -04:00
parent 9022fa7d93
commit 57abe57bc7
54 changed files with 974 additions and 206 deletions
--- a/backend/src/Socialize.Api/ApplicationRegistration.cs
+++ b/backend/src/Socialize.Api/ApplicationRegistration.cs
@@ -78,7 +78,7 @@ internal static class ApplicationRegistration
                    ValidAudience = authJwt["Audience"],
                    ValidateLifetime = true,
                    IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(authJwt["Key"] ??
-                        throw new ArgumentNullException("The Jwt Key is missing.")))
+                        throw new InvalidOperationException("Authentication:Jwt:Key is required.")))
                };
            });
        }
@@ -89,9 +89,9 @@ internal static class ApplicationRegistration
            authenticationBuilder.AddGoogle(GoogleDefaults.AuthenticationScheme, options =>
            {
                options.ClientId = authGoogle["ClientId"] ??
-                                   throw new ArgumentNullException("The Google ClientId is missing.");
+                                   throw new InvalidOperationException("Authentication:Google:ClientId is required.");
                options.ClientSecret = authGoogle["ClientSecret"] ??
-                                       throw new ArgumentNullException("The Google ClientSecret is missing.");
+                                       throw new InvalidOperationException("Authentication:Google:ClientSecret is required.");
            });
        }

@@ -101,9 +101,9 @@ internal static class ApplicationRegistration
            authenticationBuilder.AddFacebook(FacebookDefaults.AuthenticationScheme, options =>
            {
                options.ClientId = authFacebook["ClientId"] ??
-                                   throw new ArgumentNullException("The Facebook ClientId is missing.");
+                                   throw new InvalidOperationException("Authentication:Facebook:ClientId is required.");
                options.ClientSecret = authFacebook["ClientSecret"] ??
-                                       throw new ArgumentNullException("The Facebook ClientSecret is missing.");
+                                       throw new InvalidOperationException("Authentication:Facebook:ClientSecret is required.");
            });
        }

--- a/backend/src/Socialize.Api/Infrastructure/BlobStorage/Contracts/ContentTypes.cs
+++ b/backend/src/Socialize.Api/Infrastructure/BlobStorage/Contracts/ContentTypes.cs
@@ -39,6 +39,6 @@ internal static class ContentTypes

        // Check for HTML content by looking for "<!DOCTYPE html>" or "<html>" tags
        string content = Encoding.UTF8.GetString(buffer);
-        return content.Contains("<!DOCTYPE html>");
+        return content.Contains("<!DOCTYPE html>", StringComparison.OrdinalIgnoreCase);
    }
 }
--- a/backend/src/Socialize.Api/Infrastructure/BlobStorage/Services/LocalBlobStorage.cs
+++ b/backend/src/Socialize.Api/Infrastructure/BlobStorage/Services/LocalBlobStorage.cs
@@ -14,6 +14,14 @@ internal sealed class LocalBlobStorage(
    private const long MaxUploadSize = 10 * 1024 * 1024;
    private const string ContentTypeMetadataSuffix = ".content-type";

+    private static readonly char[] PathSeparators = [Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar];
+
+    private static readonly Action<ILogger, string, string, string, string, Exception?> LogUploadedFile =
+        LoggerMessage.Define<string, string, string, string>(
+            LogLevel.Information,
+            new EventId(1, nameof(UploadFileAsync)),
+            "Blob storage: Uploaded [{BlobName}] to local container [{ContainerName}] with contentType [{ContentType}] and uri [{FileUri}]");
+
    private readonly LocalBlobStorageOptions _options = options.Value;

    public async Task<string> UploadFileAsync(
@@ -46,12 +54,7 @@ internal sealed class LocalBlobStorage(
        await File.WriteAllTextAsync(GetContentTypeMetadataPath(filePath), contentType, ct);

        string fileUri = BuildPublicUrl(relativePath);
-        logger.LogInformation(
-            "Blob storage: Uploaded [{BlobName}] to local container [{ContainerName}] with contentType [{ContentType}] and uri [{FileUri}]",
-            blobName,
-            containerName,
-            contentType,
-            fileUri);
+        LogUploadedFile(logger, blobName, containerName, contentType, fileUri, null);

        return fileUri;
    }
@@ -106,7 +109,7 @@ internal sealed class LocalBlobStorage(
            throw new InvalidOperationException("Blob storage: Blob paths must be relative.");
        }

-        string[] pathParts = [containerName, .. blobName.Split([Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar])];
+        string[] pathParts = [containerName, .. blobName.Split(PathSeparators)];
        if (pathParts.Any(part => part is "" or "." or ".."))
        {
            throw new InvalidOperationException("Blob storage: Blob paths must not contain relative path segments.");
@@ -135,7 +138,7 @@ internal sealed class LocalBlobStorage(
            ? "/api/storage"
            : requestPath.Trim();

-        return normalized.StartsWith("/", StringComparison.Ordinal)
+        return normalized.StartsWith('/')
            ? normalized.TrimEnd('/')
            : $"/{normalized.TrimEnd('/')}";
    }
--- a/backend/src/Socialize.Api/Infrastructure/Emailer/Services/LoggerEmailSender.cs
+++ b/backend/src/Socialize.Api/Infrastructure/Emailer/Services/LoggerEmailSender.cs
@@ -5,14 +5,15 @@ namespace Socialize.Api.Infrastructure.Emailer.Services;
 internal class LoggerEmailSender(ILogger<IEmailSender> logger)
    : IEmailSender
 {
+    private static readonly Action<ILogger, string, string, string, string, Exception?> LogDevelopmentEmail =
+        LoggerMessage.Define<string, string, string, string>(
+            LogLevel.Information,
+            new EventId(1, nameof(SendEmailAsync)),
+            "Development email to {Email} with subject {Subject}:{NewLine}{Message}");
+
    public Task SendEmailAsync(string email, string subject, string message)
    {
-        logger.LogInformation(
-            "Development email to {Email} with subject {Subject}:{NewLine}{Message}",
-            email,
-            subject,
-            Environment.NewLine,
-            message);
+        LogDevelopmentEmail(logger, email, subject, Environment.NewLine, message, null);

        return Task.CompletedTask;
    }
--- a/backend/src/Socialize.Api/Infrastructure/Emailer/Services/ResendEmailSender.cs
+++ b/backend/src/Socialize.Api/Infrastructure/Emailer/Services/ResendEmailSender.cs
@@ -43,14 +43,13 @@ internal class ResendEmailSender : IEmailSender
            new MediaTypeWithQualityHeaderValue("application/json"));
    }

-    public async Task SendEmailAsync(string toEmail, string subject, string htmlMessage)
+    public async Task SendEmailAsync(string email, string subject, string message)
    {
-        var payload = new { from = _options.FromEmail, to = toEmail, subject, html = htmlMessage };
+        var payload = new { from = _options.FromEmail, to = email, subject, html = message };

        string json = JsonSerializer.Serialize(payload);
-        StringContent content = new(json, Encoding.UTF8, "application/json");
-
-        HttpResponseMessage response = await _httpClient.PostAsync(EndpointUri, content);
+        using StringContent content = new(json, Encoding.UTF8, "application/json");
+        using HttpResponseMessage response = await _httpClient.PostAsync(EndpointUri, content);

        if (!response.IsSuccessStatusCode)
        {
--- a/backend/src/Socialize.Api/Infrastructure/Security/AccessScopeService.cs
+++ b/backend/src/Socialize.Api/Infrastructure/Security/AccessScopeService.cs
@@ -7,49 +7,49 @@ namespace Socialize.Api.Infrastructure.Security;
 internal sealed class AccessScopeService(
    OrganizationAccessService organizationAccessService)
 {
-    public bool IsManager(ClaimsPrincipal user)
+    public static bool IsManager(ClaimsPrincipal user)
    {
        return user.IsInRole(KnownRoles.Administrator) || user.IsInRole(KnownRoles.Manager);
    }

-    public bool IsProvider(ClaimsPrincipal user)
+    public static bool IsProvider(ClaimsPrincipal user)
    {
        return user.IsInRole(KnownRoles.Provider);
    }

-    public bool IsClient(ClaimsPrincipal user)
+    public static bool IsClient(ClaimsPrincipal user)
    {
        return user.IsInRole(KnownRoles.Client);
    }

-    public bool CanAccessWorkspace(ClaimsPrincipal user, Guid workspaceId)
+    public static bool CanAccessWorkspace(ClaimsPrincipal user, Guid workspaceId)
    {
        return IsManager(user) || user.GetWorkspaceScopeIds().Contains(workspaceId);
    }

-    public bool CanManageWorkspace(ClaimsPrincipal user, Guid workspaceId)
+    public static bool CanManageWorkspace(ClaimsPrincipal user, Guid workspaceId)
    {
        return IsManager(user) && CanAccessWorkspace(user, workspaceId);
    }

-    public bool CanAccessClient(ClaimsPrincipal user, Guid workspaceId, Guid clientId)
+    public static bool CanAccessClient(ClaimsPrincipal user, Guid workspaceId, Guid clientId)
    {
        return IsManager(user)
               || (CanAccessWorkspace(user, workspaceId) && user.GetClientScopeIds().Contains(clientId));
    }

-    public bool CanAccessCampaign(ClaimsPrincipal user, Guid workspaceId, Guid clientId, Guid campaignId)
+    public static bool CanAccessCampaign(ClaimsPrincipal user, Guid workspaceId, Guid clientId, Guid campaignId)
    {
        return IsManager(user)
               || (CanAccessClient(user, workspaceId, clientId) && user.GetCampaignScopeIds().Contains(campaignId));
    }

-    public bool CanContributeToCampaign(ClaimsPrincipal user, Guid workspaceId, Guid clientId, Guid campaignId)
+    public static bool CanContributeToCampaign(ClaimsPrincipal user, Guid workspaceId, Guid clientId, Guid campaignId)
    {
        return IsManager(user) || (IsProvider(user) && CanAccessCampaign(user, workspaceId, clientId, campaignId));
    }

-    public bool CanReviewContent(ClaimsPrincipal user, Guid workspaceId, Guid clientId, Guid campaignId)
+    public static bool CanReviewContent(ClaimsPrincipal user, Guid workspaceId, Guid clientId, Guid campaignId)
    {
        return IsManager(user)
               || IsProvider(user) && CanAccessCampaign(user, workspaceId, clientId, campaignId)
--- a/backend/src/Socialize.Api/Infrastructure/Security/ClaimsPrincipalExtensions.cs
+++ b/backend/src/Socialize.Api/Infrastructure/Security/ClaimsPrincipalExtensions.cs
@@ -1,4 +1,5 @@
-using System.Security.Claims;
+using System.Globalization;
+using System.Security.Claims;

 namespace Socialize.Api.Infrastructure.Security;

@@ -81,11 +82,11 @@ internal static class ClaimsPrincipalExtensions

        if (claim is null)
        {
-            throw new MissingClaimException(key);
+            throw MissingClaimException.ForClaim(key);
        }

        return typeof(TValue) == typeof(Guid)
            ? Guid.Parse(claim.Value)
-            : Convert.ChangeType(claim.Value, typeof(TValue));
+            : Convert.ChangeType(claim.Value, typeof(TValue), CultureInfo.InvariantCulture);
    }
 }
--- a/backend/src/Socialize.Api/Infrastructure/Security/MissingClaimException.cs
+++ b/backend/src/Socialize.Api/Infrastructure/Security/MissingClaimException.cs
@@ -1,5 +1,23 @@
 namespace Socialize.Api.Infrastructure.Security;

-internal class MissingClaimException(
-    string claimName)
-    : Exception($"Claim '{claimName}' is missing.");
+public class MissingClaimException : Exception
+{
+    public MissingClaimException()
+    {
+    }
+
+    public MissingClaimException(string message)
+        : base(message)
+    {
+    }
+
+    public MissingClaimException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+
+    internal static MissingClaimException ForClaim(string claimName)
+    {
+        return new MissingClaimException($"Claim '{claimName}' is missing.");
+    }
+}
--- a/backend/src/Socialize.Api/Infrastructure/Security/PasswordGenerator.cs
+++ b/backend/src/Socialize.Api/Infrastructure/Security/PasswordGenerator.cs
@@ -11,8 +11,6 @@ internal static class PasswordGenerator
    private const string Numbers = "0123456789";
    private const string SpecialCharacters = "!@#$%^&*()_+-=[];',./`~{}|:\"<>?";

-    private static readonly Random Random = new();
-
    public static string Next(
        int length = 15,
        bool requireNumber = true,
@@ -23,7 +21,7 @@ internal static class PasswordGenerator
        // Create pools based on the requirements
        StringBuilder characterPool = new();

-        if (requireNumber)
+        if (requireLowercase)
        {
            characterPool.Append(LowerLetters);
        }
@@ -51,22 +49,22 @@ internal static class PasswordGenerator

        if (requireLowercase)
        {
-            password[index++] = LowerLetters[Random.Next(LowerLetters.Length)];
+            password[index++] = LowerLetters[RandomNumberGenerator.GetInt32(LowerLetters.Length)];
        }

        if (requireCapital)
        {
-            password[index++] = UpperLetters[Random.Next(UpperLetters.Length)];
+            password[index++] = UpperLetters[RandomNumberGenerator.GetInt32(UpperLetters.Length)];
        }

        if (requireNumber)
        {
-            password[index++] = Numbers[Random.Next(Numbers.Length)];
+            password[index++] = Numbers[RandomNumberGenerator.GetInt32(Numbers.Length)];
        }

        if (requireSpecialCharacter)
        {
-            password[index++] = SpecialCharacters[Random.Next(SpecialCharacters.Length)];
+            password[index++] = SpecialCharacters[RandomNumberGenerator.GetInt32(SpecialCharacters.Length)];
        }

        // Fill the rest with the password
@@ -85,7 +83,7 @@ internal static class PasswordGenerator
    {
        for (int i = array.Length - 1; i > 0; i--)
        {
-            int j = Random.Next(i + 1);
+            int j = RandomNumberGenerator.GetInt32(i + 1);
            (array[i], array[j]) = (array[j], array[i]); // Swap elements
        }
    }
--- a/backend/src/Socialize.Api/Infrastructure/TestData/TestDataSeedExtensions.cs
+++ b/backend/src/Socialize.Api/Infrastructure/TestData/TestDataSeedExtensions.cs
@@ -19,6 +19,8 @@ using Microsoft.AspNetCore.Identity;

 namespace Socialize.Api.Infrastructure.TestData;

+#pragma warning disable S1075 // Test data intentionally uses representative external URLs.
+
 internal static class TestDataSeedExtensions
 {
    private static readonly Guid OrganizationId = Guid.Parse("99999999-9999-9999-9999-999999999999");
@@ -209,13 +211,7 @@ internal static class TestDataSeedExtensions
            await userManager.RemoveClaimAsync(user, claim);
        }

-        string persona = roles.Contains(KnownRoles.Manager, StringComparer.Ordinal)
-            ? KnownRoles.Manager
-            : roles.Contains(KnownRoles.Client, StringComparer.Ordinal)
-                ? KnownRoles.Client
-                : roles.Contains(KnownRoles.Provider, StringComparer.Ordinal)
-                    ? KnownRoles.Provider
-                    : KnownRoles.WorkspaceMember;
+        string persona = GetPersona(roles);

        foreach (Claim claim in claims.Concat([new Claim(KnownClaims.Persona, persona)]))
        {
@@ -225,6 +221,26 @@ internal static class TestDataSeedExtensions
        return user;
    }

+    private static string GetPersona(IReadOnlyCollection<string> roles)
+    {
+        if (roles.Contains(KnownRoles.Manager, StringComparer.Ordinal))
+        {
+            return KnownRoles.Manager;
+        }
+
+        if (roles.Contains(KnownRoles.Client, StringComparer.Ordinal))
+        {
+            return KnownRoles.Client;
+        }
+
+        if (roles.Contains(KnownRoles.Provider, StringComparer.Ordinal))
+        {
+            return KnownRoles.Provider;
+        }
+
+        return KnownRoles.WorkspaceMember;
+    }
+
    private static async Task EnsureOrganizationDataAsync(
        Guid managerUserId,
        Guid developerUserId,
--- a/backend/src/Socialize.Api/Migrations/20260507143849_Initial.cs
+++ b/backend/src/Socialize.Api/Migrations/20260507143849_Initial.cs
@@ -5,6 +5,7 @@ using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
 #nullable disable

 #pragma warning disable CA1814 // Prefer jagged arrays over multidimensional
+#pragma warning disable CA1861 // Generated migration seed arrays are not runtime hot paths.

 namespace Socialize.Api.Migrations
 {
--- a/backend/src/Socialize.Api/Modules/Approvals/Handlers/SubmitApprovalDecision.cs
+++ b/backend/src/Socialize.Api/Modules/Approvals/Handlers/SubmitApprovalDecision.cs
@@ -8,6 +8,7 @@ using Socialize.Api.Modules.Approvals.Data;
 using Socialize.Api.Modules.Approvals.Services;
 using Socialize.Api.Modules.Notifications.Contracts;
 using Socialize.Api.Modules.Workspaces.Data;
+using System.Security.Claims;
 using System.Text.Json;

 namespace Socialize.Api.Modules.Approvals.Handlers;
@@ -79,12 +80,14 @@ internal class SubmitApprovalDecisionHandler(
        }

        string normalizedDecision = request.Decision.Trim();
-        string decidedByName = User?.Identity?.IsAuthenticated == true
-            ? User.GetAlias() ?? User.GetName()
-            : string.IsNullOrWhiteSpace(request.ReviewerName) ? approval.ReviewerName : request.ReviewerName.Trim();
-        string decidedByEmail = User?.Identity?.IsAuthenticated == true
-            ? User.GetEmail()
-            : string.IsNullOrWhiteSpace(request.ReviewerEmail) ? approval.ReviewerEmail : request.ReviewerEmail.Trim();
+        ClaimsPrincipal? currentUser = User;
+        bool isAuthenticated = currentUser?.Identity?.IsAuthenticated == true;
+        string decidedByName = isAuthenticated
+            ? currentUser!.GetAlias() ?? currentUser!.GetName()
+            : GetReviewerName(request.ReviewerName, approval.ReviewerName);
+        string decidedByEmail = isAuthenticated
+            ? currentUser!.GetEmail()
+            : GetReviewerEmail(request.ReviewerEmail, approval.ReviewerEmail);

        ApprovalDecision decision = new()
        {
@@ -207,4 +210,18 @@ internal class SubmitApprovalDecisionHandler(

        await SendOkAsync(dto, ct);
    }
+
+    private static string GetReviewerName(string? requestedName, string fallbackName)
+    {
+        return string.IsNullOrWhiteSpace(requestedName)
+            ? fallbackName
+            : requestedName.Trim();
+    }
+
+    private static string GetReviewerEmail(string? requestedEmail, string fallbackEmail)
+    {
+        return string.IsNullOrWhiteSpace(requestedEmail)
+            ? fallbackEmail
+            : requestedEmail.Trim();
+    }
 }
--- a/backend/src/Socialize.Api/Modules/Approvals/Services/ApprovalWorkflowRuntimeService.cs
+++ b/backend/src/Socialize.Api/Modules/Approvals/Services/ApprovalWorkflowRuntimeService.cs
@@ -145,13 +145,15 @@ internal class ApprovalWorkflowRuntimeService(
        dbContext.ApprovalDecisions.Add(decision);
        await dbContext.SaveChangesAsync(ct);

-        int approvedCount = await dbContext.ApprovalDecisions
+        var approvalDecisionParticipants = await dbContext.ApprovalDecisions
            .Where(candidate => candidate.ApprovalRequestId == approval.Id && candidate.Decision == ApprovedState)
            .Select(candidate => candidate.DecidedByUserId.HasValue
                ? candidate.DecidedByUserId.Value.ToString()
-                : candidate.DecidedByEmail.ToLower())
-            .Distinct()
-            .CountAsync(ct);
+                : candidate.DecidedByEmail)
+            .ToListAsync(ct);
+        int approvedCount = approvalDecisionParticipants
+            .Distinct(StringComparer.OrdinalIgnoreCase)
+            .Count();

        int requiredApproverCount = approval.WorkflowStepRequiredApproverCount ?? 1;
        if (!ApprovalWorkflowRules.HasRequiredStepApprovals(approvedCount, requiredApproverCount))
@@ -394,7 +396,7 @@ internal class ApprovalWorkflowRuntimeService(

    private static string CreateAccessToken()
    {
-        return Convert.ToHexString(RandomNumberGenerator.GetBytes(16)).ToLowerInvariant();
+        return Convert.ToHexString(RandomNumberGenerator.GetBytes(16));
    }

    private sealed record ApprovalNotificationRecipient(Guid UserId, string? Email);
--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/Data/CalendarCatalogSeed.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/Data/CalendarCatalogSeed.cs
@@ -1,5 +1,7 @@
 namespace Socialize.Api.Modules.CalendarIntegrations.Data;

+#pragma warning disable S1075 // Catalog seed entries intentionally store source URLs.
+
 internal static class CalendarCatalogSeed
 {
    public static readonly CalendarCatalogEntry[] Entries =
--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/Handlers/CreateCalendarSource.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/Handlers/CreateCalendarSource.cs
@@ -121,7 +121,7 @@ internal class CreateCalendarSourceHandler(
             source.CatalogSourceReference == normalizedCatalogReference) ||
            (!string.IsNullOrWhiteSpace(normalizedUrl) &&
             source.SourceUrl != null &&
-             source.SourceUrl.ToUpper() == normalizedUrl.ToUpper()),
+             EF.Functions.ILike(source.SourceUrl, normalizedUrl)),
            ct);
    }

--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/Handlers/ListCalendarCatalog.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/Handlers/ListCalendarCatalog.cs
@@ -47,11 +47,11 @@ internal class ListCalendarCatalogHandler(AppDbContext dbContext)

        if (!string.IsNullOrWhiteSpace(request.Search))
        {
-            string search = request.Search.Trim().ToLowerInvariant();
+            string search = $"%{request.Search.Trim()}%";
            query = query.Where(entry =>
-                entry.Title.ToLower().Contains(search) ||
-                entry.Description.ToLower().Contains(search) ||
-                entry.ProviderName.ToLower().Contains(search));
+                EF.Functions.ILike(entry.Title, search) ||
+                EF.Functions.ILike(entry.Description, search) ||
+                EF.Functions.ILike(entry.ProviderName, search));
        }

        if (!string.IsNullOrWhiteSpace(request.Country))
--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/ModuleRegistration.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/ModuleRegistration.cs
@@ -4,8 +4,6 @@ internal static class ModuleRegistration
 {
    public static WebApplicationBuilder AddCalendarIntegrationsModule(this WebApplicationBuilder builder)
    {
-        builder.Services.AddSingleton<Services.IcsCalendarParser>();
-        builder.Services.AddSingleton<Services.CalendarExportFeedBuilder>();
        builder.Services.AddScoped<Services.CalendarExportFeedService>();
        builder.Services.AddScoped<Services.CalendarImportSyncService>();
        builder.Services.AddHostedService<Services.CalendarImportBackgroundService>();
--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/CalendarExportFeedBuilder.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/CalendarExportFeedBuilder.cs
@@ -1,4 +1,5 @@
 using System.Text;
+using System.Globalization;

 namespace Socialize.Api.Modules.CalendarIntegrations.Services;

@@ -11,9 +12,9 @@ internal sealed record CalendarExportFeedEvent(
    string? Description,
    string? Url);

-internal class CalendarExportFeedBuilder
+internal static class CalendarExportFeedBuilder
 {
-    public string Build(string calendarName, IReadOnlyCollection<CalendarExportFeedEvent> events)
+    public static string Build(string calendarName, IReadOnlyCollection<CalendarExportFeedEvent> events)
    {
        StringBuilder builder = new();
        builder.AppendLine("BEGIN:VCALENDAR");
@@ -21,34 +22,34 @@ internal class CalendarExportFeedBuilder
        builder.AppendLine("PRODID:-//Socialize//User Work Calendar//EN");
        builder.AppendLine("CALSCALE:GREGORIAN");
        builder.AppendLine("METHOD:PUBLISH");
-        builder.AppendLine($"X-WR-CALNAME:{EscapeText(calendarName)}");
+        AppendLineInvariant(builder, $"X-WR-CALNAME:{EscapeText(calendarName)}");

        foreach (CalendarExportFeedEvent feedEvent in events.OrderBy(calendarEvent => calendarEvent.StartsAt))
        {
            builder.AppendLine("BEGIN:VEVENT");
-            builder.AppendLine($"UID:{EscapeText(feedEvent.Uid)}");
-            builder.AppendLine($"DTSTAMP:{FormatUtc(DateTimeOffset.UtcNow)}");
-            builder.AppendLine($"SUMMARY:{EscapeText(feedEvent.Title)}");
+            AppendLineInvariant(builder, $"UID:{EscapeText(feedEvent.Uid)}");
+            AppendLineInvariant(builder, $"DTSTAMP:{FormatUtc(DateTimeOffset.UtcNow)}");
+            AppendLineInvariant(builder, $"SUMMARY:{EscapeText(feedEvent.Title)}");

            if (feedEvent.IsAllDay)
            {
-                builder.AppendLine($"DTSTART;VALUE=DATE:{FormatDate(feedEvent.StartsAt)}");
-                builder.AppendLine($"DTEND;VALUE=DATE:{FormatDate(feedEvent.EndsAt)}");
+                AppendLineInvariant(builder, $"DTSTART;VALUE=DATE:{FormatDate(feedEvent.StartsAt)}");
+                AppendLineInvariant(builder, $"DTEND;VALUE=DATE:{FormatDate(feedEvent.EndsAt)}");
            }
            else
            {
-                builder.AppendLine($"DTSTART:{FormatUtc(feedEvent.StartsAt)}");
-                builder.AppendLine($"DTEND:{FormatUtc(feedEvent.EndsAt)}");
+                AppendLineInvariant(builder, $"DTSTART:{FormatUtc(feedEvent.StartsAt)}");
+                AppendLineInvariant(builder, $"DTEND:{FormatUtc(feedEvent.EndsAt)}");
            }

            if (!string.IsNullOrWhiteSpace(feedEvent.Description))
            {
-                builder.AppendLine($"DESCRIPTION:{EscapeText(feedEvent.Description)}");
+                AppendLineInvariant(builder, $"DESCRIPTION:{EscapeText(feedEvent.Description)}");
            }

            if (!string.IsNullOrWhiteSpace(feedEvent.Url))
            {
-                builder.AppendLine($"URL:{EscapeText(feedEvent.Url)}");
+                AppendLineInvariant(builder, $"URL:{EscapeText(feedEvent.Url)}");
            }

            builder.AppendLine("END:VEVENT");
@@ -71,10 +72,15 @@ internal class CalendarExportFeedBuilder
    private static string EscapeText(string value)
    {
        return value
-            .Replace("\\", "\\\\")
-            .Replace("\r\n", "\\n")
-            .Replace("\n", "\\n")
-            .Replace(";", "\\;")
-            .Replace(",", "\\,");
+            .Replace("\\", "\\\\", StringComparison.Ordinal)
+            .Replace("\r\n", "\\n", StringComparison.Ordinal)
+            .Replace("\n", "\\n", StringComparison.Ordinal)
+            .Replace(";", "\\;", StringComparison.Ordinal)
+            .Replace(",", "\\,", StringComparison.Ordinal);
+    }
+
+    private static void AppendLineInvariant(StringBuilder builder, FormattableString value)
+    {
+        builder.AppendLine(value.ToString(CultureInfo.InvariantCulture));
    }
 }
--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/CalendarExportFeedService.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/CalendarExportFeedService.cs
@@ -3,11 +3,11 @@ using Socialize.Api.Data;

 namespace Socialize.Api.Modules.CalendarIntegrations.Services;

-internal class CalendarExportFeedService(AppDbContext dbContext, CalendarExportFeedBuilder feedBuilder)
+internal class CalendarExportFeedService(AppDbContext dbContext)
 {
    public async Task<string> BuildUserFeedAsync(Guid userId, string? userEmail, string appBaseUrl, CancellationToken ct)
    {
-        string normalizedEmail = userEmail?.Trim().ToUpperInvariant() ?? string.Empty;
+        string normalizedEmail = userEmail?.Trim() ?? string.Empty;
        Guid[] workspaceIds = await dbContext.Workspaces
            .Where(workspace =>
                workspace.OwnerUserId == userId ||
@@ -51,7 +51,7 @@ internal class CalendarExportFeedService(AppDbContext dbContext, CalendarExportF
            .Where(approval =>
                approval.DueAt.HasValue &&
                (approval.RequestedByUserId == userId ||
-                 (!string.IsNullOrEmpty(normalizedEmail) && approval.ReviewerEmail.ToUpper() == normalizedEmail)))
+                 (!string.IsNullOrEmpty(normalizedEmail) && EF.Functions.ILike(approval.ReviewerEmail, normalizedEmail))))
            .Join(
                dbContext.ContentItems,
                approval => approval.ContentItemId,
@@ -91,7 +91,7 @@ internal class CalendarExportFeedService(AppDbContext dbContext, CalendarExportF
                appBaseUrl))
            .ToListAsync(ct));

-        return feedBuilder.Build("Socialize my work", events);
+        return CalendarExportFeedBuilder.Build("Socialize my work", events);
    }

    private static CalendarExportFeedEvent ToContentFeedEvent(
--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/CalendarImportBackgroundService.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/CalendarImportBackgroundService.cs
@@ -23,12 +23,15 @@ internal sealed class CalendarImportBackgroundService(
            CalendarImportSyncService syncService = scope.ServiceProvider.GetRequiredService<CalendarImportSyncService>();
            await syncService.RefreshDueSourcesAsync(stoppingToken);
        }
-        catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
+        catch (OperationCanceledException ex) when (stoppingToken.IsCancellationRequested)
        {
+            logger.LogDebug(ex, "Calendar import background sync stopped.");
        }
+#pragma warning disable CA1031 // Background service should log and continue after unexpected sync failures.
        catch (Exception ex)
        {
            logger.LogError(ex, "Calendar import background sync failed.");
        }
+#pragma warning restore CA1031
    }
 }
--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/CalendarImportSyncService.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/CalendarImportSyncService.cs
@@ -1,15 +1,19 @@
 using Microsoft.EntityFrameworkCore;
 using Socialize.Api.Data;
 using Socialize.Api.Modules.CalendarIntegrations.Data;
+using System.Globalization;
 using System.Text.Json;

 namespace Socialize.Api.Modules.CalendarIntegrations.Services;

+#pragma warning disable S1075 // Supplemental observance identifiers intentionally use stable URI-like values.
+
 internal sealed class CalendarImportSyncService(
    AppDbContext dbContext,
-    IHttpClientFactory httpClientFactory,
-    IcsCalendarParser parser)
+    IHttpClientFactory httpClientFactory)
 {
+    private static readonly JsonSerializerOptions JsonSerializerOptions = new(JsonSerializerDefaults.Web);
+
    public async Task RefreshSourceAsync(Guid sourceId, CancellationToken ct)
    {
        CalendarSource? source = await dbContext.CalendarSources
@@ -115,7 +119,7 @@ internal sealed class CalendarImportSyncService(
        }
    }

-    private async Task<IReadOnlyCollection<ParsedCalendarEvent>> GetParsedEventsAsync(
+    private static async Task<IReadOnlyCollection<ParsedCalendarEvent>> GetParsedEventsAsync(
        HttpClient httpClient,
        string sourceUrl,
        DateOnly rangeStart,
@@ -127,8 +131,8 @@ internal sealed class CalendarImportSyncService(
            return await GetNagerEventsAsync(httpClient, sourceUrl, countryCode!, rangeStart, rangeEnd, ct);
        }

-        string content = await httpClient.GetStringAsync(sourceUrl, ct);
-        return parser.Parse(content, rangeStart, rangeEnd);
+        string content = await httpClient.GetStringAsync(new Uri(sourceUrl), ct);
+        return IcsCalendarParser.Parse(content, rangeStart, rangeEnd);
    }

    private static async Task<IReadOnlyCollection<ParsedCalendarEvent>> GetNagerEventsAsync(
@@ -143,14 +147,12 @@ internal sealed class CalendarImportSyncService(
        for (int year = rangeStart.Year; year <= rangeEnd.Year; year++)
        {
            string yearUrl = BuildNagerYearUrl(sourceUrl, countryCode, year);
-            string json = await httpClient.GetStringAsync(yearUrl, ct);
-            NagerHoliday[] holidays = JsonSerializer.Deserialize<NagerHoliday[]>(
-                json,
-                new JsonSerializerOptions(JsonSerializerDefaults.Web)) ?? [];
+            string json = await httpClient.GetStringAsync(new Uri(yearUrl), ct);
+            NagerHoliday[] holidays = JsonSerializer.Deserialize<NagerHoliday[]>(json, JsonSerializerOptions) ?? [];

            foreach (NagerHoliday holiday in holidays)
            {
-                if (!DateOnly.TryParse(holiday.Date, out DateOnly date) ||
+                if (!DateOnly.TryParse(holiday.Date, CultureInfo.InvariantCulture, out DateOnly date) ||
                    date < rangeStart ||
                    date > rangeEnd)
                {
@@ -283,7 +285,7 @@ internal sealed class CalendarImportSyncService(
    private static string NormalizeUidPart(string? value)
    {
        return new string((value ?? "holiday")
-            .ToLowerInvariant()
+            .ToUpperInvariant()
            .Select(character => char.IsLetterOrDigit(character) ? character : '-')
            .ToArray())
            .Trim('-');
--- a/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/IcsCalendarParser.cs
+++ b/backend/src/Socialize.Api/Modules/CalendarIntegrations/Services/IcsCalendarParser.cs
@@ -1,4 +1,5 @@
 using System.Globalization;
+using System.Text;

 namespace Socialize.Api.Modules.CalendarIntegrations.Services;

@@ -39,9 +40,9 @@ internal sealed record IcsRawEvent(
    string? SourceUrl,
    DateTimeOffset? LastModifiedAt);

-internal sealed class IcsCalendarParser
+internal static class IcsCalendarParser
 {
-    public IReadOnlyCollection<ParsedCalendarEvent> Parse(
+    public static IReadOnlyCollection<ParsedCalendarEvent> Parse(
        string content,
        DateOnly rangeStart,
        DateOnly rangeEnd)
@@ -63,10 +64,12 @@ internal sealed class IcsCalendarParser
    private static IEnumerable<IcsRawEvent> ReadRawEvents(string content)
    {
        List<string> lines = UnfoldLines(content).ToList();
-        for (int index = 0; index < lines.Count; index++)
+        int index = 0;
+        while (index < lines.Count)
        {
            if (!lines[index].Equals("BEGIN:VEVENT", StringComparison.OrdinalIgnoreCase))
            {
+                index++;
                continue;
            }

@@ -74,9 +77,10 @@ internal sealed class IcsCalendarParser
                new(StringComparer.OrdinalIgnoreCase);

            index++;
-            for (; index < lines.Count && !lines[index].Equals("END:VEVENT", StringComparison.OrdinalIgnoreCase); index++)
+            while (index < lines.Count && !lines[index].Equals("END:VEVENT", StringComparison.OrdinalIgnoreCase))
            {
                ParseProperty(lines[index], properties);
+                index++;
            }

            if (!TryGetFirst(properties, "DTSTART", out var startProperty))
@@ -105,32 +109,34 @@ internal sealed class IcsCalendarParser
                TryGetFirst(properties, "LAST-MODIFIED", out var lastModified)
                    ? ParseDateTimeValue(lastModified.Value, lastModified.Parameters).UtcDateTime
                    : null);
+
+            index++;
        }
    }

    private static IEnumerable<string> UnfoldLines(string content)
    {
-        string? current = null;
+        StringBuilder? current = null;
        using StringReader reader = new(content.Replace("\r\n", "\n", StringComparison.Ordinal).Replace('\r', '\n'));
        while (reader.ReadLine() is { } line)
        {
            if ((line.StartsWith(' ') || line.StartsWith('\t')) && current is not null)
            {
-                current += line[1..];
+                current.Append(line[1..]);
                continue;
            }

            if (current is not null)
            {
-                yield return current;
+                yield return current.ToString();
            }

-            current = line;
+            current = new StringBuilder(line);
        }

        if (current is not null)
        {
-            yield return current;
+            yield return current.ToString();
        }
    }

@@ -309,7 +315,7 @@ internal sealed class IcsCalendarParser
        return TimeSpan.Zero;
    }

-    private static IReadOnlyCollection<DateOnly> ExpandStartDates(
+    private static List<DateOnly> ExpandStartDates(
        IcsRawEvent rawEvent,
        DateOnly rangeStart,
        DateOnly rangeEnd)
--- a/backend/src/Socialize.Api/Modules/Campaigns/Handlers/GetCampaigns.cs
+++ b/backend/src/Socialize.Api/Modules/Campaigns/Handlers/GetCampaigns.cs
@@ -34,7 +34,7 @@ internal class GetCampaignsHandler(
    {
        IQueryable<Campaign> query = dbContext.Campaigns.AsQueryable();

-        if (!accessScopeService.IsManager(User))
+        if (!AccessScopeService.IsManager(User))
        {
            IReadOnlyCollection<Guid> workspaceScopeIds = await accessScopeService.GetAccessibleWorkspaceIdsAsync(User, ct);
            IReadOnlyCollection<Guid> clientScopeIds = User.GetClientScopeIds();
--- a/backend/src/Socialize.Api/Modules/Channels/Handlers/GetChannels.cs
+++ b/backend/src/Socialize.Api/Modules/Channels/Handlers/GetChannels.cs
@@ -23,7 +23,7 @@ internal class GetChannelsHandler(
    {
        IQueryable<Channel> query = dbContext.Channels.AsQueryable();

-        if (!accessScopeService.IsManager(User))
+        if (!AccessScopeService.IsManager(User))
        {
            IReadOnlyCollection<Guid> workspaceScopeIds = await accessScopeService.GetAccessibleWorkspaceIdsAsync(User, ct);
            query = query.Where(channel => workspaceScopeIds.Contains(channel.WorkspaceId));
--- a/backend/src/Socialize.Api/Modules/Clients/Handlers/GetClients.cs
+++ b/backend/src/Socialize.Api/Modules/Clients/Handlers/GetClients.cs
@@ -33,7 +33,7 @@ internal class GetClientsHandler(
    {
        IQueryable<Client> query = dbContext.Clients.AsQueryable();

-        if (!accessScopeService.IsManager(User))
+        if (!AccessScopeService.IsManager(User))
        {
            IReadOnlyCollection<Guid> workspaceScopeIds = await accessScopeService.GetAccessibleWorkspaceIdsAsync(User, ct);
            IReadOnlyCollection<Guid> clientScopeIds = User.GetClientScopeIds();
--- a/backend/src/Socialize.Api/Modules/Comments/Handlers/CreateComment.cs
+++ b/backend/src/Socialize.Api/Modules/Comments/Handlers/CreateComment.cs
@@ -96,7 +96,7 @@ internal class CreateCommentHandler(

        if (request.Attachment is not null)
        {
-            string normalizedContentType = request.Attachment.ContentType.Trim().ToLowerInvariant();
+            string normalizedContentType = request.Attachment.ContentType.Trim();

            if (request.Attachment.Length <= 0)
            {
@@ -213,17 +213,26 @@ internal class CreateCommentHandler(

    private static bool IsInlineAttachmentContentType(string contentType)
    {
-        return contentType.Trim().ToLowerInvariant() is "image/png" or "image/jpeg" or "image/jpg";
+        string normalized = contentType.Trim();
+        return normalized.Equals("image/png", StringComparison.OrdinalIgnoreCase) ||
+               normalized.Equals("image/jpeg", StringComparison.OrdinalIgnoreCase) ||
+               normalized.Equals("image/jpg", StringComparison.OrdinalIgnoreCase);
    }

    private static string NormalizeFileName(string? fileName, string contentType)
    {
-        string extension = contentType.Trim().ToLowerInvariant() switch
+        string normalizedContentType = contentType.Trim();
+        string extension = string.Empty;
+        if (normalizedContentType.Equals("image/png", StringComparison.OrdinalIgnoreCase))
        {
-            "image/png" => ".png",
-            "image/jpeg" or "image/jpg" => ".jpg",
-            _ => string.Empty,
-        };
+            extension = ".png";
+        }
+        else if (normalizedContentType.Equals("image/jpeg", StringComparison.OrdinalIgnoreCase) ||
+                 normalizedContentType.Equals("image/jpg", StringComparison.OrdinalIgnoreCase))
+        {
+            extension = ".jpg";
+        }
+
        string normalized = Path.GetFileName(fileName ?? string.Empty).Trim();
        if (string.IsNullOrWhiteSpace(normalized))
        {
--- a/backend/src/Socialize.Api/Modules/ContentItems/Handlers/GetContentItems.cs
+++ b/backend/src/Socialize.Api/Modules/ContentItems/Handlers/GetContentItems.cs
@@ -37,7 +37,7 @@ internal class GetContentItemsHandler(
    {
        IQueryable<ContentItem> query = dbContext.ContentItems.AsQueryable();

-        if (!accessScopeService.IsManager(User))
+        if (!AccessScopeService.IsManager(User))
        {
            IReadOnlyCollection<Guid> workspaceScopeIds = await accessScopeService.GetAccessibleWorkspaceIdsAsync(User, ct);
            IReadOnlyCollection<Guid> clientScopeIds = User.GetClientScopeIds();
--- a/backend/src/Socialize.Api/Modules/Feedback/Handlers/UpdateDeveloperFeedback.cs
+++ b/backend/src/Socialize.Api/Modules/Feedback/Handlers/UpdateDeveloperFeedback.cs
@@ -169,13 +169,12 @@ internal class UpdateDeveloperFeedbackHandler(
            .ToHashSet(StringComparer.Ordinal);

        bool changed = false;
-        foreach (FeedbackTag existingTag in report.Tags.ToArray())
+        foreach (FeedbackTag existingTag in report.Tags
+                     .Where(existingTag => !requestedKeys.Contains(existingTag.NormalizedName))
+                     .ToArray())
        {
-            if (!requestedKeys.Contains(existingTag.NormalizedName))
-            {
-                report.Tags.Remove(existingTag);
-                changed = true;
-            }
+            report.Tags.Remove(existingTag);
+            changed = true;
        }

        HashSet<string> existingKeys = report.Tags
--- a/backend/src/Socialize.Api/Modules/Identity/Handlers/ChangeEmail.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Handlers/ChangeEmail.cs
@@ -1,6 +1,7 @@
 using FastEndpoints;
 using Socialize.Api.Infrastructure.Security;
 using Socialize.Api.Modules.Identity.Data;
+using Socialize.Api.Modules.Identity.Services;
 using Microsoft.AspNetCore.Identity;

 namespace Socialize.Api.Modules.Identity.Handlers;
@@ -9,10 +10,15 @@ namespace Socialize.Api.Modules.Identity.Handlers;
 internal record ChangeEmailRequest(
    string? Email);

+[PublicAPI]
+internal record ChangeEmailResponse(
+    string Message);
+
 [PublicAPI]
 internal class ChangeEmailHandler(
-    UserManager userManager)
-    : Endpoint<ChangeEmailRequest>
+    UserManager userManager,
+    EmailVerificationService emailVerificationService)
+    : Endpoint<ChangeEmailRequest, ChangeEmailResponse>
 {
    public override void Configure()
    {
@@ -32,18 +38,28 @@ internal class ChangeEmailHandler(
            return;
        }

-        user.Email = request.Email;
-
-        // TODO: check to see if identity resets the `email confirmed` flag - @jonathan
-        IdentityResult result = await userManager.UpdateAsync(user);
-
-        if (result.Succeeded)
+        if (string.IsNullOrWhiteSpace(request.Email))
        {
-            await SendOkAsync(ct);
+            await SendStringAsync(
+                "Email is required",
+                400,
+                cancellation: ct);
+            return;
        }
-        else
+
+        string newEmail = request.Email.Trim();
+        if (string.Equals(user.Email, newEmail, StringComparison.OrdinalIgnoreCase))
        {
-            await SendUnauthorizedAsync(ct);
+            await SendOkAsync(
+                new ChangeEmailResponse("Email is already set to this address."),
+                ct);
+            return;
        }
+
+        await emailVerificationService.SendEmailChangeConfirmationAsync(user, newEmail);
+
+        await SendOkAsync(
+            new ChangeEmailResponse("Please check your new email address to confirm the change."),
+            ct);
    }
 }
--- a/backend/src/Socialize.Api/Modules/Identity/Handlers/ChangePhone.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Handlers/ChangePhone.cs
@@ -32,10 +32,22 @@ internal class ChangePhoneHandler(
            return;
        }

-        user.PhoneNumber = request.PhoneNumber;
-        // TODO: check to see if identity resets the `phone confirmed` flag - @jonathan
+        string? newPhoneNumber = string.IsNullOrWhiteSpace(request.PhoneNumber)
+            ? null
+            : request.PhoneNumber.Trim();

-        IdentityResult result = await userManager.UpdateAsync(user);
+        IdentityResult result;
+        if (newPhoneNumber is null)
+        {
+            user.PhoneNumber = null;
+            user.PhoneNumberConfirmed = false;
+            result = await userManager.UpdateAsync(user);
+        }
+        else
+        {
+            string token = await userManager.GenerateChangePhoneNumberTokenAsync(user, newPhoneNumber);
+            result = await userManager.ChangePhoneNumberAsync(user, newPhoneNumber, token);
+        }

        if (result.Succeeded)
        {
--- a/backend/src/Socialize.Api/Modules/Identity/Handlers/ConfirmEmailChange.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Handlers/ConfirmEmailChange.cs
@@ -0,0 +1,70 @@
+using FastEndpoints;
+using Microsoft.AspNetCore.Identity;
+using System.Web;
+using Socialize.Api.Modules.Identity.Data;
+
+namespace Socialize.Api.Modules.Identity.Handlers;
+
+[PublicAPI]
+internal record ConfirmEmailChangeRequest(
+    string UserId,
+    string Email,
+    string Token);
+
+[PublicAPI]
+internal record ConfirmEmailChangeResponse(
+    string Message);
+
+[PublicAPI]
+internal class ConfirmEmailChangeHandler(
+    UserManager userManager)
+    : Endpoint<ConfirmEmailChangeRequest, ConfirmEmailChangeResponse>
+{
+    public override void Configure()
+    {
+        AllowAnonymous();
+        Get("/api/users/confirm-email-change");
+        Options(o => o.WithTags("Users"));
+    }
+
+    public override async Task HandleAsync(
+        ConfirmEmailChangeRequest request,
+        CancellationToken ct)
+    {
+        User? user = await userManager.FindByIdAsync(request.UserId);
+        if (user is null)
+        {
+            await SendStringAsync(
+                "Invalid email change link",
+                400,
+                cancellation: ct);
+            return;
+        }
+
+        string newEmail = request.Email.Trim();
+        string decodedToken = HttpUtility.UrlDecode(request.Token).Replace(" ", "+", StringComparison.Ordinal);
+        IdentityResult result = await userManager.ChangeEmailAsync(user, newEmail, decodedToken);
+        if (!result.Succeeded)
+        {
+            await SendStringAsync(
+                "Invalid email change link or the link has expired",
+                400,
+                cancellation: ct);
+            return;
+        }
+
+        IdentityResult usernameResult = await userManager.SetUserNameAsync(user, newEmail);
+        if (!usernameResult.Succeeded)
+        {
+            await SendStringAsync(
+                usernameResult.Errors.First().Description,
+                400,
+                cancellation: ct);
+            return;
+        }
+
+        await SendOkAsync(
+            new ConfirmEmailChangeResponse("Email address changed successfully."),
+            ct);
+    }
+}
--- a/backend/src/Socialize.Api/Modules/Identity/Handlers/GetCurrentUser.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Handlers/GetCurrentUser.cs
@@ -18,13 +18,13 @@ internal class GetCurrentUserQueryHandler(
    }

    public override async Task HandleAsync(
-        CancellationToken cancellationToken)
+        CancellationToken ct)
    {
        UserModel? userModel = await identityService.GetCurrentUserAsync();

        if (userModel is null)
        {
-            await SendNotFoundAsync(cancellationToken);
+            await SendNotFoundAsync(ct);
            return;
        }

@@ -76,6 +76,6 @@ internal class GetCurrentUserQueryHandler(
                Address = userModel.Address,
                UserRoles = roles
            },
-            cancellationToken);
+            ct);
    }
 }
--- a/backend/src/Socialize.Api/Modules/Identity/Handlers/GetCurrentUserProfilePicture.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Handlers/GetCurrentUserProfilePicture.cs
@@ -19,21 +19,21 @@ internal class GetCurrentUserPortraitHandler(
    }

    public override async Task HandleAsync(
-        CancellationToken cancellationToken)
+        CancellationToken ct)
    {
        UserModel? identityUser = await identityService.GetCurrentUserAsync();

        if (identityUser is null)
        {
-            await SendNotFoundAsync(cancellationToken);
+            await SendNotFoundAsync(ct);
            return;
        }

        MemoryStream stream = await blobStorage.DownloadFileAsync(
            ContainerNames.Users,
            $"{identityUser.Id.ToString()}/{SubDirectoryNames.Profile}/{CommonFileNames.ProfilePicture}",
-            cancellationToken);
+            ct);

-        await SendOkAsync(stream, cancellationToken);
+        await SendOkAsync(stream, ct);
    }
 }
--- a/backend/src/Socialize.Api/Modules/Identity/Handlers/LoginWithFacebook.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Handlers/LoginWithFacebook.cs
@@ -61,9 +61,8 @@ internal class LoginWithFacebookHandler(
    {
        // Verify the token with Facebook
        using HttpClient httpClient = httpClientFactory.CreateClient();
-        using HttpResponseMessage response = await httpClient.GetAsync(
-            $"https://graph.facebook.com/me?access_token={request.Token}&fields=id,name,email,picture.width(200).height(200)",
-            ct);
+        Uri userInfoUri = new($"https://graph.facebook.com/me?access_token={request.Token}&fields=id,name,email,picture.width(200).height(200)");
+        using HttpResponseMessage response = await httpClient.GetAsync(userInfoUri, ct);
        if (!response.IsSuccessStatusCode)
        {
            await SendStringAsync(
--- a/backend/src/Socialize.Api/Modules/Identity/Handlers/LoginWithGoogle.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Handlers/LoginWithGoogle.cs
@@ -63,9 +63,8 @@ internal class LoginWithGoogleHandler(

        // Verify the token with Google
        using HttpClient httpClient = httpClientFactory.CreateClient();
-        using HttpResponseMessage response = await httpClient.GetAsync(
-            $"https://www.googleapis.com/oauth2/v1/userinfo?access_token={googleToken.AccessToken}",
-            ct);
+        Uri userInfoUri = new($"https://www.googleapis.com/oauth2/v1/userinfo?access_token={googleToken.AccessToken}");
+        using HttpResponseMessage response = await httpClient.GetAsync(userInfoUri, ct);
        if (!response.IsSuccessStatusCode)
        {
            await SendStringAsync(
--- a/backend/src/Socialize.Api/Modules/Identity/Handlers/VerifyEmail.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Handlers/VerifyEmail.cs
@@ -42,8 +42,7 @@ internal class VerifyEmailHandler(
        }

        // Verify the token and confirm email
-        string decoded = HttpUtility.UrlDecode(request.Token);
-        string decodedWithPlus = request.Token.Replace(" ", "+");
+        string decodedWithPlus = HttpUtility.UrlDecode(request.Token).Replace(" ", "+", StringComparison.Ordinal);
        IdentityResult result = await userManager.ConfirmEmailAsync(user, decodedWithPlus);
        if (!result.Succeeded)
        {
--- a/backend/src/Socialize.Api/Modules/Identity/Services/AccessTokenFactory.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Services/AccessTokenFactory.cs
@@ -16,13 +16,7 @@ internal sealed class AccessTokenFactory(
        IList<string> roles = await userManager.GetRolesAsync(user);
        IList<Claim> claims = await userManager.GetClaimsAsync(user);

-        string persona = roles.Contains(KnownRoles.Manager, StringComparer.Ordinal)
-            ? KnownRoles.Manager
-            : roles.Contains(KnownRoles.Client, StringComparer.Ordinal)
-                ? KnownRoles.Client
-                : roles.Contains(KnownRoles.Provider, StringComparer.Ordinal)
-                    ? KnownRoles.Provider
-                    : KnownRoles.WorkspaceMember;
+        string persona = GetPersona(roles);

        List<Claim> tokenClaims = [.. claims, new Claim(KnownClaims.Persona, persona)];

@@ -40,4 +34,24 @@ internal sealed class AccessTokenFactory(
            roles,
            tokenClaims);
    }
+
+    private static string GetPersona(IList<string> roles)
+    {
+        if (roles.Contains(KnownRoles.Manager, StringComparer.Ordinal))
+        {
+            return KnownRoles.Manager;
+        }
+
+        if (roles.Contains(KnownRoles.Client, StringComparer.Ordinal))
+        {
+            return KnownRoles.Client;
+        }
+
+        if (roles.Contains(KnownRoles.Provider, StringComparer.Ordinal))
+        {
+            return KnownRoles.Provider;
+        }
+
+        return KnownRoles.WorkspaceMember;
+    }
 }
--- a/backend/src/Socialize.Api/Modules/Identity/Services/EmailVerificationService.cs
+++ b/backend/src/Socialize.Api/Modules/Identity/Services/EmailVerificationService.cs
@@ -58,4 +58,52 @@ internal sealed class EmailVerificationService(
             </div>
             """);
    }
+
+    public async Task SendEmailChangeConfirmationAsync(
+        User user,
+        string newEmail)
+    {
+        string token = await userManager.GenerateChangeEmailTokenAsync(user, newEmail);
+        string encodedEmail = HttpUtility.UrlEncode(newEmail);
+        string encodedToken = HttpUtility.UrlEncode(token);
+        string confirmationLink =
+            $"{options.Value.FrontendBaseUrl}/verify-email?changeEmail=true&userId={user.Id}&email={encodedEmail}&token={encodedToken}";
+
+        await emailSender.SendEmailAsync(
+            newEmail,
+            "Confirm your new email address",
+            $"""
+             <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto; padding: 20px; color: #333;">
+               <h1 style="color: #2c3e50; margin-bottom: 20px;">Confirm your new email address</h1>
+
+               <p style="font-size: 16px; line-height: 1.5; margin-bottom: 25px;">
+                 Please confirm this email address for your Socialize account by clicking the button below:
+               </p>
+
+               <div style="text-align: center; margin: 30px 0;">
+                 <a href='{confirmationLink}'
+                    style="background-color: #3498db;
+                           color: white;
+                           text-decoration: none;
+                           padding: 12px 24px;
+                           border-radius: 4px;
+                           font-weight: bold;
+                           display: inline-block;
+                           box-shadow: 0 2px 5px rgba(0,0,0,0.1);">
+                   Confirm Email Address
+                 </a>
+               </div>
+
+               <p style="font-size: 14px; color: #7f8c8d; margin-top: 30px;">
+                 If you did not request this change, please ignore this email.
+               </p>
+
+               <p style="font-size: 14px; color: #7f8c8d; margin-top: 20px;">
+                 If the button doesn't work, you can copy and paste this link into your browser:
+                 <br>
+                 <a href='{confirmationLink}' style="color: #3498db; word-break: break-all;">{confirmationLink}</a>
+               </p>
+             </div>
+             """);
+    }
 }
--- a/backend/src/Socialize.Api/Modules/Notifications/Handlers/GetNotifications.cs
+++ b/backend/src/Socialize.Api/Modules/Notifications/Handlers/GetNotifications.cs
@@ -56,7 +56,7 @@ internal class GetNotificationsHandler(
        IQueryable<NotificationEvent> query = dbContext.NotificationEvents.AsQueryable();
        Guid currentUserId = User.GetUserId();

-        if (!accessScopeService.IsManager(User))
+        if (!AccessScopeService.IsManager(User))
        {
            IReadOnlyCollection<Guid> workspaceScopeIds = await accessScopeService.GetAccessibleWorkspaceIdsAsync(User, ct);
            query = query.Where(notificationEvent =>
--- a/backend/src/Socialize.Api/Modules/Organizations/Services/OrganizationAccessService.cs
+++ b/backend/src/Socialize.Api/Modules/Organizations/Services/OrganizationAccessService.cs
@@ -9,7 +9,7 @@ namespace Socialize.Api.Modules.Organizations.Services;
 internal sealed class OrganizationAccessService(
    AppDbContext dbContext)
 {
-    public bool IsGlobalManager(ClaimsPrincipal user)
+    public static bool IsGlobalManager(ClaimsPrincipal user)
    {
        return user.IsInRole(KnownRoles.Administrator) || user.IsInRole(KnownRoles.Manager);
    }
--- a/backend/src/Socialize.Api/Modules/Workspaces/Handlers/CreateWorkspaceInvite.cs
+++ b/backend/src/Socialize.Api/Modules/Workspaces/Handlers/CreateWorkspaceInvite.cs
@@ -4,6 +4,7 @@ using Socialize.Api.Data;
 using Socialize.Api.Infrastructure.Security;
 using Socialize.Api.Modules.Identity.Contracts;
 using Socialize.Api.Modules.Workspaces.Data;
+using System.Globalization;

 namespace Socialize.Api.Modules.Workspaces.Handlers;

@@ -59,7 +60,9 @@ internal class CreateWorkspaceInviteHandler(
            return;
        }

-        string normalizedEmail = request.Email.Trim().ToLowerInvariant();
+#pragma warning disable CA1308 // Email addresses are conventionally normalized to lowercase for storage and lookup.
+        string normalizedEmail = request.Email.Trim().ToLower(CultureInfo.InvariantCulture);
+#pragma warning restore CA1308
        string normalizedRole = request.Role.Trim();

        bool duplicateInvite = await dbContext.WorkspaceInvites.AnyAsync(
--- a/backend/src/Socialize.Api/Program.cs
+++ b/backend/src/Socialize.Api/Program.cs
@@ -22,6 +22,8 @@ using Socialize.Api.Modules.Organizations;
 using Socialize.Api.Modules.Workspaces;


+const string SeededTestDataMessage = "Seeded test data.";
+
 var builder = WebApplication.CreateBuilder(args);
 bool seedTestData = args.Any(arg => string.Equals(arg, "seed-testdata", StringComparison.OrdinalIgnoreCase));

@@ -94,7 +96,7 @@ if (seedTestData)
    await app.UseAppDataAsync();
    await app.UseIdentityModuleAsync();
    await app.Services.SeedTestDataAsync();
-    Console.WriteLine("Seeded test data.");
+    Console.WriteLine(SeededTestDataMessage);
    return;
 }

--- a/backend/src/Socialize.Api/Socialize.Api.csproj
+++ b/backend/src/Socialize.Api/Socialize.Api.csproj
@@ -9,7 +9,7 @@
    <!-- Enable code analysis -->
    <EnableNETAnalyzers>true</EnableNETAnalyzers>
    <AnalysisMode>AllEnabledByDefault</AnalysisMode>
-    <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
    <WarningsAsErrors />
    <NoWarn>$(NoWarn);CA2007</NoWarn> <!-- disable ConfigureAwait warning - not present in ASP.NET Core -->
    <EnableDefaultEmbeddedResourceItems>false</EnableDefaultEmbeddedResourceItems>
--- a/backend/tests/Socialize.Tests/CalendarIntegrations/CalendarExportFeedTests.cs
+++ b/backend/tests/Socialize.Tests/CalendarIntegrations/CalendarExportFeedTests.cs
@@ -29,8 +29,7 @@ public class CalendarExportFeedTests
    [Fact]
    public void Build_emits_valid_ics_for_user_work_without_sensitive_discussion_details()
    {
-        CalendarExportFeedBuilder builder = new();
-        string ics = builder.Build(
+        string ics = CalendarExportFeedBuilder.Build(
            "Socialize my work",
            [
                new CalendarExportFeedEvent(
--- a/backend/tests/Socialize.Tests/CalendarIntegrations/IcsCalendarParserTests.cs
+++ b/backend/tests/Socialize.Tests/CalendarIntegrations/IcsCalendarParserTests.cs
@@ -4,8 +4,6 @@ namespace Socialize.Tests.CalendarIntegrations;

 public class IcsCalendarParserTests
 {
-    private readonly IcsCalendarParser _parser = new();
-
    [Fact]
    public void Parse_preserves_all_day_calendar_dates()
    {
@@ -20,7 +18,7 @@ public class IcsCalendarParserTests
                     END:VCALENDAR
                     """;

-        ParsedCalendarEvent calendarEvent = Assert.Single(_parser.Parse(
+        ParsedCalendarEvent calendarEvent = Assert.Single(IcsCalendarParser.Parse(
            ics,
            new DateOnly(2026, 12, 1),
            new DateOnly(2026, 12, 31)));
@@ -45,7 +43,7 @@ public class IcsCalendarParserTests
                     END:VCALENDAR
                     """;

-        ParsedCalendarEvent calendarEvent = Assert.Single(_parser.Parse(
+        ParsedCalendarEvent calendarEvent = Assert.Single(IcsCalendarParser.Parse(
            ics,
            new DateOnly(2026, 5, 1),
            new DateOnly(2026, 5, 31)));
@@ -70,7 +68,7 @@ public class IcsCalendarParserTests
                     END:VCALENDAR
                     """;

-        ParsedCalendarEvent calendarEvent = Assert.Single(_parser.Parse(
+        ParsedCalendarEvent calendarEvent = Assert.Single(IcsCalendarParser.Parse(
            ics,
            new DateOnly(2026, 5, 1),
            new DateOnly(2026, 5, 31)));
@@ -96,7 +94,7 @@ public class IcsCalendarParserTests
                     END:VCALENDAR
                     """;

-        IReadOnlyCollection<ParsedCalendarEvent> events = _parser.Parse(
+        IReadOnlyCollection<ParsedCalendarEvent> events = IcsCalendarParser.Parse(
            ics,
            new DateOnly(2026, 1, 1),
            new DateOnly(2027, 12, 31));
@@ -122,7 +120,7 @@ public class IcsCalendarParserTests
                     END:VCALENDAR
                     """;

-        ParsedCalendarEvent calendarEvent = Assert.Single(_parser.Parse(
+        ParsedCalendarEvent calendarEvent = Assert.Single(IcsCalendarParser.Parse(
            ics,
            new DateOnly(2026, 5, 1),
            new DateOnly(2026, 5, 31)));