Add remote subscription support so spokes can consume streaming operations
over pubsub transports (WebSocket, Redis). Extract checkAccess to access.ts
to break circular dep between call.ts and subscribe.ts.
- Remove PendingRequestMap interface from env.ts (had reduced signature missing deadline, identity typed as unknown)
- Add CallMap interface in env.ts with full call() signature matching the class
- Update EnvOptions.callMap to use CallMap type
- Export PendingRequestMap class directly (remove PendingRequestMapClass alias)
- Export CallMap type from index.ts instead of old PendingRequestMap interface
