Bug: Cloud-proxy calls continue after switching to local backend

Steps to Reproduce

1. Register both a local agent-server backend and an OH cloud backend
2. Start with the cloud backend as active
3. Switch to the local backend

Expected Behavior

When switching to a local backend, there should be NO calls to /api/cloud-proxy (method: OPTIONS) since that is only for cloud backend communication.

Actual Behavior

Network inspector shows continuous OPTIONS requests to:

• http://127.0.0.1:8000/api/cloud-proxy (method: OPTIONS, status: 200)

These requests happen every ~10 seconds, continuing indefinitely after switching away from the cloud backend to a local one.

Possible Cause

Two hooks make unconditional calls to cloud backends:

1. useBackendsHealth (src/hooks/query/use-backends-health.ts:91)

   • Polls ALL registered backends every 10 seconds
   • Calls getCurrentCloudApiKey(backend) → callCloudProxy() → /api/cloud-proxy for cloud backends
   • Issue: Does not check if the backend is the active one before polling

2. useAllCloudOrganizations (src/hooks/query/use-cloud-organizations.ts:16)

   • Fetches organizations for ALL cloud backends (not just the active one)
   • Used by the backend selector dropdown

Neither hook gates on whether the backend is the active one - they iterate through every registered backend regardless of the active selection.