## Why
Interrupting a turn or terminating a Code Mode cell can drop a pending dynamic tool handler before it publishes its completion. Cancellation needs to settle the call in live events and persisted history without allowing a late response into model context.
## What changed
- Let dynamic tool handlers observe cancellation and publish their terminal item before dispatch finishes. Calls cancelled while awaiting a response complete with a failed item and a cancellation error.
- Keep readiness, dispatch admission, registry lock waits, hooks, and output processing cancellable so cancellation can finish even when a hook is blocked.
- Report an aborted tool lifecycle outcome when cancellation interrupts dispatch, including before handler execution.
## Testing
Add regression tests for turn interruption with pending calls or blocked hooks, cell termination with persisted failure and late-response exclusion, cancellation before dispatch admission, and exactly one completion when a response races cancellation.
GitOrigin-RevId: 0112fc74c8652c91503ed5bbfb334ae2e26930ef
mikelam-oai
18e28fe1b9