## What changed
- Use a never-resolving promise when verifying that a session continues to
enforce its yield limit after terminating a cell.
- Use `yield_control()` to create the yielded cell in the notification-draining
test instead of relying on timer scheduling.
GitOrigin-RevId: 01cdaa94e5b8b5c89c6fa98c4bbdb28a690678e0
## What changed
- Subscribe each gRPC code-mode session to nested tool calls and forward tool and notification callbacks to its delegate.
- Complete tool calls through the host while bounding oversized results and errors.
- Track callback ownership and cancellation so completed cells drain notifications, terminated cells cancel them, and shutdown revokes outstanding work.
- Validate callback identifiers, cell ownership, enabled tools, and pending callback limits without serializing independent callbacks or sessions.
## Testing
- Add integration and state tests for callback forwarding, completion ordering, cancellation, malformed callbacks, delegate panics, oversized results, and concurrent work.
GitOrigin-RevId: 005afbb90eea0eb77d746b930a1a96ca6dfcd4e7
Channing Conger