feat: handle inter-pod heartbeat requests

Merged
HA
2mo ago
+220-6

Closes: #71

Summary by cubic

Forwards viewer heartbeats to the pod that owns the room when the viewer is connected to a different pod. Previously, heartbeats only updated the local room state; now the owning pod updates the viewer's heartbeat and responds, while the local pod skips its own heartbeat update.

Notes

  • Adds a 5-second timeout for cross-pod heartbeat requests; failed, timed-out, or misconfigured (missing room node) requests are logged and skipped.
  • The receiving pod validates the viewer is in the room before updating the heartbeat.
  • Documents the cross-pod heartbeat flow in docs/MultiplePodSignaling/heartBeat.md.