fix(cli): add session path tracking to prevent crashes during parallel tasks

[cruzanstx]

Summary

• Fixes "Process exited unexpectedly" errors when mobile users send messages during parallel Task subagent execution with worktrees
• Adds session path tracking so sessions created in different directories validate correctly

Problem

When running parallel Task subagents (e.g., via worktrees):

1. Claude Code may create new sessions in different working directories (worktrees)
2. Happy CLI detects the new session ID but validates it against the original path
3. Session file exists in the worktree path, not the original path
4. Validation fails and crashes

Solution

Track the path where each session was created and use that path for validation:

• Added SessionInfo interface with id and path fields
• sessionId getter maintains backward compatibility
• claudeCheckSession() now accepts optional sessionPath parameter
• Extract cwd from SDKSystemMessage during session discovery

Test plan

• yarn build passes
• yarn test passes (102 tests)
• Manual test: Start Happy CLI, run parallel tasks in worktrees, verify no crashes

Generated with Claude Code via Happy

Co-Authored-By: Claude [email protected]
Co-Authored-By: Codex [email protected]

[cruzanstx]

Manual Test Results

Tested the session path tracking fix with parallel Task subagents.

Test Scenario

1. Started Happy CLI session in a test directory
2. Ran 3 parallel Task agents with subagent_type=Explore targeting different directories
3. Monitored for "Process exited unexpectedly" errors

Results

Check	Result
Session started in test directory	Pass
Parallel Task subagents executed	Pass
No "Process exited unexpectedly" errors	Pass
Session remained running after parallel tasks	Pass
Session responsive (ready state)	Pass

Verification

• Confirmed session_id and cwd are properly tracked in logs
• Session hook correctly captured session path
• No crashes observed when sending messages during parallel task execution

The fix successfully prevents crashes when Task subagents operate in different working directories.