fix(tunnels): connect tool containers to backend network for cloudflared access

apps/api/src/services/docker.py

@@ -173,6 +173,24 @@ def get_container_name(instance_name: str) -> str | None:
     return None
 
 
+def connect_container_to_network(container_name: str, network_name: str = "backend") -> bool:
+    """Connect a Docker container to an existing network.
+
+    Args:
+        container_name: Name or ID of the container
+        network_name: Name of the Docker network (default: backend)
+
+    Returns:
+        True if successful, False otherwise
+    """
+    result = subprocess.run(
+        ["docker", "network", "connect", network_name, container_name],
+        capture_output=True,
+        text=True,
+    )
+    return result.returncode == 0
+
+
 def get_container_status(container_id: str) -> str:
     """Get the status of a Docker container.