Refactor self-connection handling and improve message processing

- Removed self-connection detection logic from the Listener and Server, simplifying the message handling process.
- Updated the HandleMessage and handle-websocket functions to eliminate checks for self-connections, enhancing clarity and maintainability.
- Adjusted AUTH challenge logic to focus solely on blacklisted IPs, streamlining connection management.

app/server.go

@@ -49,33 +49,6 @@ type Server struct {
 	policyManager    *policy.P
 }
 
-// isSelfConnection checks if the connection is coming from the relay itself
-func (s *Server) isSelfConnection(remote string) bool {
-	// Check for localhost connections
-	if strings.HasPrefix(remote, "127.0.0.1:") || strings.HasPrefix(remote, "::1:") || strings.HasPrefix(remote, "[::1]:") {
-		return true
-	}
-
-	// Check for connections from the same IP as the server
-	// This handles cases where the relay connects to itself via its public IP
-	if s.Config.Listen != "" {
-		// Extract IP from listen address (e.g., "0.0.0.0" -> "0.0.0.0")
-		listenIP := s.Config.Listen
-		if listenIP == "0.0.0.0" || listenIP == "" {
-			// If listening on all interfaces, check if remote IP matches any local interface
-			// For now, we'll be conservative and only check localhost
-			return false
-		}
-		// Check if remote IP matches the listen IP
-		remoteIP := strings.Split(remote, ":")[0]
-		if remoteIP == listenIP {
-			return true
-		}
-	}
-
-	return false
-}
-
 // isIPBlacklisted checks if an IP address is blacklisted using the managed ACL system
 func (s *Server) isIPBlacklisted(remote string) bool {
 	// Extract IP from remote address (e.g., "192.168.1.1:12345" -> "192.168.1.1")