fix(runtime): terminate turns on terminal errors

[ALV0612]

Summary

• treat matching root-turn app-server error notifications with willRetry: false as terminal failed turns
• keep willRetry: true errors non-terminal so valid retries can complete
• preserve the exact error in failed task/review payloads, rendered output, and tracked job state
• keep unrelated and tracked-subagent errors from overwriting the result-authoritative root turn

Root cause

captureTurn() recorded an error notification and emitted a cosmetic failed progress phase, but never settled state.completion. When Codex did not send a later turn/completed, the companion and broker stayed alive indefinitely while the job remained running / failed.

The generated protocol includes willRetry, so only a non-retryable error is terminal. This patch synthesizes a complete failed Turn and routes it through the existing idempotent completeTurn() path. A later turn/completed cannot overwrite that first terminal transition.

Testing

• node --test --test-name-pattern='(non-retryable turn error|terminal failure|retryable turn error|unrelated thread|review terminates|tracked subagent error)' tests/runtime.test.mjs — 7/7 pass
• npm test — 98/98 pass
• npm run build — pass
• npm run check-version — pass
• git diff --check — pass

Regression coverage includes:

• terminal error after turn/start acknowledgement
• terminal error buffered before acknowledgement
• terminal error followed by a contradictory completion
• retryable error followed by success
• unrelated-thread error isolation
• tracked-subagent error isolation
• native review error rendering and terminal persisted state

Fixes #698