Enhance Telegram channel validation in UserService and Formatings

- Updated UpdateTelegramChannel method to support both numeric channel IDs and Telegram URL formats.
- Improved error handling for invalid formats, ensuring clear exceptions for users.
- Refactored Formatings class to extract numeric channel IDs from URLs and handle formatting consistently.

src/Managing.Common/Formatings.cs

@@ -1,3 +1,5 @@
+using System.Text.RegularExpressions;
+
 namespace Managing.Common;
 
 public static class Formatings
@@ -9,15 +11,35 @@ public static class Formatings
             return string.Empty;
         }
 
-        if (telegramChannel.StartsWith("100"))
+        // If it's a URL format, extract the numeric channel ID
+        if (telegramChannel.StartsWith("https://web.telegram.org/k/#", StringComparison.OrdinalIgnoreCase))
         {
-            return telegramChannel.Substring(3);
-        }
-        else if (telegramChannel.StartsWith("-100"))
-        {
-            return telegramChannel.Substring(4);
+            var match = Regex.Match(telegramChannel, @"#-?(\d{5,15})$");
+            if (match.Success)
+            {
+                // Extract the numeric ID (without the leading minus if present)
+                var channelId = match.Groups[1].Value;
+                return FormatNumericChannelId(channelId);
+            }
+            // If URL format but can't extract ID, return as-is (shouldn't happen if validation is correct)
+            return telegramChannel;
         }
 
-        return telegramChannel;
+        // Handle numeric channel IDs
+        return FormatNumericChannelId(telegramChannel);
+    }
+
+    private static string FormatNumericChannelId(string channelId)
+    {
+        if (channelId.StartsWith("100"))
+        {
+            return channelId.Substring(3);
+        }
+        else if (channelId.StartsWith("-100"))
+        {
+            return channelId.Substring(4);
+        }
+
+        return channelId;
     }
 }