- Add structured warning logs in silent catch paths for IPC worker shutdown, plugin unregistration cleanup, child runtime metrics polling, and merger build rollback reset
- Improve merger rollback warning context to make build-verification reset and retry failures easier to diagnose
- Add regression tests covering each new warning path to ensure errors are surfaced without changing existing control flow
- Add StepSessionExecutor test coverage for cherry-pick abort logging when conflict cleanup fails
- Remove unused imports across 25 files in engine package
- Remove unused variable declarations in ipc-worker.ts, child-process-runtime.ts, and mission-autopilot.ts
- Clean up unnecessary imports in agent-instructions.ts, agent-tools.ts, cron-runner.ts, executor.ts, and other modules
- Minor cleanup in notifier.ts, peer-exchange-service.ts, pi.ts, plugin-runner.ts, and other files
- Improves code quality and reduces potential confusion from unused code
- Add generation tracking plus dedicated SIGKILL and restart timer fields in ChildProcessRuntime
- Guard delayed kill/restart callbacks so stale generations and stopping runtimes are ignored
- Clear pending lifecycle timers during stop and before rescheduling to prevent stacked callbacks
- Expand child-process runtime tests to cover timer cancellation, generation safety, and spawn generation increments
- Define ProjectRuntime interface with unified task execution contract\n- Implement IPC protocol for host-worker communication (messages, streaming, heartbeats)\n- Add InProcessRuntime for synchronous in-process task execution\n- Add ChildProcessRuntime with isolated worker processes for sandboxed execution\n- Implement ProjectManager to coordinate runtime selection and task lifecycle\n- Update engine exports to expose runtime APIs\n- Add comprehensive tests for all runtime implementations and IPC protocol
