feat: enhance IRC support with display name handling, private channel tracking, and connection identification

src/EchoHub.Core/DTOs/ProfileDtos.cs

@@ -30,6 +30,7 @@ public record UserPresenceDto(
     string? NicknameColor,
     UserStatus Status,
     string? StatusMessage,
-    ServerRole Role);
+    ServerRole Role,
+    bool IsIrc = false);
 
 public record AvatarUploadResponse(string AvatarAscii);