fix(docker): tolerate Docker 403 on network connect when already connected

[rdemeritt]

Summary

• Docker Desktop returns HTTP 403 (not 409) with "endpoint with name ... already exists in network" when a container is already a member of the target network
• dockerNetworkConnect only tolerated 409, so the 403 propagated and aborted route provisioning — causing every deploy to fail with Docker proxy error 403
• Fix: detect the specific 403 message and treat it as the existing 409 no-op (container already connected → continue)
• Real proxy-denied 403s (different message or no message) still propagate as errors

Root cause trace

Deploy triggered
→ provisionTraefikRouteForCompose discovers container
→ dockerNetworkConnect('coolify', containerId)
  → Docker returns 403 {"message":"endpoint … already exists in network coolify"}
  → was thrown → route file never written → deploy error shown in UI

Test plan

• Deploy cantaconmigo from localhost:9080/sites/d6cbjlrcw092dfy5fwx4p0md — no error
• API logs show already on coolify network — OK then route written
• cantaconmigo.hh still resolves after re-deploy
• Proxy-denied 403 (unmanaged container) still propagates as error