many fixes and improvements - rework for modules/ and common/

feat(emailer): add Postmark and Resend providers

backend/Infrastructure/Emailer/Services/LoggerEmailSender.cs

@@ -0,0 +1,22 @@
+using Hutopy.Infrastructure.Emailer.Contracts;
+
+namespace Hutopy.Infrastructure.Emailer.Services;
+
+public class LoggerEmailSender(ILogger<IEmailSender> logger)
+    : IEmailSender
+{
+    public async Task SendEmailAsync(string email, string subject, string message)
+    {
+        try
+        {
+            logger.LogInformation("Sending email to {Email} with subject: {Subject}", email, subject);
+            await Task.Delay(1000);
+            logger.LogInformation("Email sent successfully to {Email}", email);
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Failed to send email to {Email}", email);
+            throw;
+        }
+    }
+}

backend/Infrastructure/Emailer/Services/PostmarkEmailSender.cs

@@ -0,0 +1,37 @@
+using Hutopy.Infrastructure.Emailer.Configuration;
+using Hutopy.Infrastructure.Emailer.Contracts;
+using Microsoft.Extensions.Options;
+using PostmarkDotNet;
+
+namespace Hutopy.Infrastructure.Emailer.Services;
+
+public class PostmarkEmailSender : IEmailSender
+{
+    private readonly PostmarkClient _client;
+    private readonly EmailerOptions _options;
+
+    public PostmarkEmailSender(IOptions<EmailerOptions> options)
+    {
+        _options = options.Value;
+        _client = new PostmarkClient(_options.ApiKey);
+    }
+
+    public async Task SendEmailAsync(string email, string subject, string message)
+    {
+        PostmarkResponse? sendResult = await _client.SendMessageAsync(new PostmarkMessage
+        {
+            From = _options.FromEmail,
+            To = email,
+            Subject = subject,
+            HtmlBody = message,
+            TrackOpens = true,
+            MessageStream = "outbound" // Optional: use "broadcast" for bulk
+        });
+
+        if (sendResult.Status != PostmarkStatus.Success)
+        {
+            throw new InvalidOperationException(
+                $"Postmark failed to send email: {sendResult.Message}");
+        }
+    }
+}

backend/Infrastructure/Emailer/Services/ResendEmailSender.cs

@@ -0,0 +1,46 @@
+using System.Net.Http.Headers;
+using System.Text;
+using System.Text.Json;
+using Hutopy.Infrastructure.Emailer.Configuration;
+using Hutopy.Infrastructure.Emailer.Contracts;
+using Microsoft.Extensions.Options;
+
+namespace Hutopy.Infrastructure.Emailer.Services;
+
+public class ResendEmailSender : IEmailSender
+{
+    private static readonly Uri EndpointUri = new("https://api.resend.com/emails");
+    private readonly HttpClient _httpClient;
+    private readonly EmailerOptions _options;
+
+    public ResendEmailSender(
+        IHttpClientFactory httpClientFactory,
+        IOptions<EmailerOptions> options)
+    {
+        _httpClient = httpClientFactory.CreateClient();
+        _options = options.Value;
+
+        _httpClient.DefaultRequestHeaders.Authorization =
+            new AuthenticationHeaderValue("Bearer", _options.ApiKey);
+
+        _httpClient.DefaultRequestHeaders.Accept.Add(
+            new MediaTypeWithQualityHeaderValue("application/json"));
+    }
+
+    public async Task SendEmailAsync(string toEmail, string subject, string htmlMessage)
+    {
+        var payload = new { from = _options.FromEmail, to = toEmail, subject, html = htmlMessage };
+
+        string json = JsonSerializer.Serialize(payload);
+        StringContent content = new(json, Encoding.UTF8, "application/json");
+
+        HttpResponseMessage response = await _httpClient.PostAsync(EndpointUri, content);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            string body = await response.Content.ReadAsStringAsync();
+            throw new InvalidOperationException(
+                $"Resend email failed: {response.StatusCode} - {body}");
+        }
+    }
+}