Sync Google Agents

Trigger a synchronous sync of all Google CES + DFCX agents for the org.

Returns a result dict with counts of created/updated/removed agents per provider and any per-location errors encountered during the sync.

Accepts an optional JSON body. When sync_all is explicitly false and dfcx_agent_ids / ces_keys are provided, only those agents are synced and mark-removed is skipped. Any other body (or no body) triggers a full sync.