fix(#178): route task results to parent session via correct session ID

[randomm]

Summary

• Fixed session ID mismatch causing async task results to never reach parent agent
• Added parent_session_id to typeMetadata for explicit parent/child separation
• Results now stored and retrieved by parent session ID
• Auto-wakeup events correctly target parent session
• Updated fork-features manifest with new criticalCode marker

Changes

• async-tasks.ts: Added parent_session_id field, updated 4 lookups to use it
• task.ts: Set session_id to child, parent_session_id to parent, pass parent as tracking key

Fixes #178

[randomm]

Code Review: PR #179

Summary

This PR correctly fixes the session ID routing bug in the async task system by introducing parent_session_id to separate child (for tracking) from parent (for result delivery) concerns.

✅ Approved (with minor observations)

What Works Well

1. Root Cause Identified Correctly: The issue is clearly understood - results stored under child ID but retrieved by parent ID.
2. Clean Design: Adding parent_session_id provides explicit separation of concerns.
3. Minimal/Surgical Changes: Only 7 line edits across 2 files + manifest update - exactly whats needed.
4. All Tests Pass: 1069 tests passing, CI green ✅
5. Fork Features Manifest Updated: parent_session_id added to criticalCode markers.

Session ID Routing Validation

✅ Result Delivery: Bus events target parent_session_id (lines 220, 255 in async-tasks.ts) - CORRECT
✅ Result Retrieval: getAndClearCompletedTasks() filters by parent_session_id (line 329) - CORRECT
✅ Undelivered Check: hasUndeliveredCompletedTasks() filters by parent_session_id (line 355) - CORRECT
✅ Auto-Wakeup: Handler checks event.properties.parentSessionID (line 468) - CORRECT

Cancellation Logic Validation

✅ cancelBackgroundTask() (lines 541-545): Cancels metadata?.session_id (child session) - CORRECT
✅ cleanupSessionMaps() (lines 562, 574, 583): All use session_id (child) - CORRECT, this cleans childs resources

Backward Compatibility

✅ No Breaking Changes: TaskMetadata is used in runtime Maps, not persisted. Old metadata objects in memory wont have parent_session_id, but:

• Optional chaining (?.) handles missing parent_session_id
• Existing pending tasks will complete and deliver to parent correctly
• No schema migration needed

Test Coverage Observation

Minor Note: No explicit regression tests in this PR for the core bug fix (parent receiving child results). The existing test suite passes, but future changes should consider adding an integration test that:

1. Spawns a parent agent
2. Parent spawns a subagent via /task
3. Subagent creates a background task
4. Background task completes
5. Parent receives the result via auto-wakeup

This is not blocking - existing test coverage (check_task.test.ts, 5 passing tests) is sufficient for this fix.

Final Assessment

Status: ✅ APPROVED
CI/CD: ✅ All checks passing
Merge Ready: YES

Key Points

• Correctly fixes the reported bug (#178)
• Session ID routing is now correct for all paths
• Cancellation and cleanup use appropriate IDs
• Type change is backward compatible (runtime-only data)
• Fork manifest updated with criticalCode marker

The fix is minimal, correct, and well-documented. Ready to merge.