debug: add extensive logging to recreate_tunnel_endpoint

Adds INFO-level logging to trace exactly what happens during tunnel
recreation: container lookup, network membership, target IP/URL,
tunnel creation result, health check, and direct curl probe from API.

This will help diagnose why recreated tunnels return 502 while
original tunnels work.

Quality gates: ruff clean

apps/api/src/services/docker.py

@@ -318,9 +318,7 @@ def get_container_ip_on_network(
     return None
 
 
-def is_container_on_network(
-    container_id: str, network_name: str | None = None
-) -> bool:
+def is_container_on_network(container_id: str, network_name: str | None = None) -> bool:
     """Check whether a container is already attached to a Docker network.
 
     Args: