Move Fail2Ban exceptions into central app.exceptions module

backend/app/exceptions.py

@@ -27,6 +27,24 @@ class ServerOperationError(Exception):
     """Raised when a server control command (e.g. refresh) fails."""
 
 
+class Fail2BanConnectionError(Exception):
+    """Raised when the fail2ban socket is unreachable or returns an error."""
+
+    def __init__(self, message: str, socket_path: str) -> None:
+        """Initialize with a human-readable message and the socket path.
+
+        Args:
+            message: Description of the connection problem.
+            socket_path: The fail2ban socket path that was targeted.
+        """
+        self.socket_path: str = socket_path
+        super().__init__(f"{message} (socket: {socket_path})")
+
+
+class Fail2BanProtocolError(Exception):
+    """Raised when the response from fail2ban cannot be parsed."""
+
+
 class FilterInvalidRegexError(Exception):
     """Raised when a regex pattern fails to compile."""