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

feat(emailer): add Postmark and Resend providers

backend/Infrastructure/YouTube/YouTubeUrlHelper.cs

@@ -0,0 +1,64 @@
+using System.Text.RegularExpressions;
+
+namespace Hutopy.Infrastructure.YouTube;
+
+public static class YouTubeUrlHelper
+{
+    private static readonly Regex VideoIdRegex = new(
+        @"(?:youtube\.com/(?:[^/]+/.+/|(?:v|e(?:mbed)?)/|.*[?&]v=)|youtu\.be/)([^""&?/\s]{11})",
+        RegexOptions.Compiled | RegexOptions.IgnoreCase);
+
+    private static readonly Regex ShortUrlRegex = new(
+        @"^[a-zA-Z0-9_-]{11}$",
+        RegexOptions.Compiled);
+
+    /// <summary>
+    /// Extracts the video ID from a YouTube URL or returns the input if it's already a video ID.
+    /// </summary>
+    /// <param name="input">The YouTube URL or video ID</param>
+    /// <returns>The extracted video ID or null if invalid</returns>
+    public static string? ExtractVideoId(string? input)
+    {
+        if (string.IsNullOrWhiteSpace(input))
+            return null;
+
+        // If it's already a valid video ID, return it
+        if (IsValidVideoId(input))
+            return input;
+
+        // Try to extract video ID from URL
+        var match = VideoIdRegex.Match(input);
+        return match.Success ? match.Groups[1].Value : null;
+    }
+
+    /// <summary>
+    /// Validates if the input is a valid YouTube video ID.
+    /// </summary>
+    /// <param name="input">The video ID to validate</param>
+    /// <returns>True if the input is a valid video ID</returns>
+    public static bool IsValidVideoId(string? input)
+    {
+        if (string.IsNullOrWhiteSpace(input))
+            return false;
+
+        return ShortUrlRegex.IsMatch(input);
+    }
+
+    /// <summary>
+    /// Validates if the input is a valid YouTube URL or video ID.
+    /// </summary>
+    /// <param name="input">The URL or video ID to validate</param>
+    /// <returns>True if the input is a valid YouTube URL or video ID</returns>
+    public static bool IsValidYouTubeUrlOrId(string? input)
+    {
+        if (string.IsNullOrWhiteSpace(input))
+            return false;
+
+        // Check if it's a valid video ID
+        if (IsValidVideoId(input))
+            return true;
+
+        // Check if it's a valid YouTube URL
+        return VideoIdRegex.IsMatch(input);
+    }
+}