Fix merge race condition — add retry loop on push failure in mergeWorktree

[xliry]

Problem

mergeWorktree() in src/worktree.ts has a TOCTOU race condition. Two agents finish within seconds of each other, both call mergeWorktree() on the same workspace:

1. Agent A pulls main, merges its branch
2. Agent B pulls main at the same moment, merges its branch
3. Agent A pushes successfully
4. Agent B's push fails because main moved forward
5. Silent data loss — Agent B's code never reaches main

The function returns success: false but the task was already marked completed by Claude. The work is lost.

What to do

In src/worktree.ts, mergeWorktree() function:

1. After push fails, add a retry loop (max 3 attempts):
   • git reset --hard HEAD~1 (undo the merge)
   • git pull --ff-only origin main (get latest)
   • git merge <branch> --no-edit (re-merge)
   • git push origin HEAD (try again)
2. If all 3 retries fail, return success: false with a clear error
3. Log each retry attempt

Acceptance

• Push failure triggers retry with fresh pull
• Max 3 retry attempts before giving up
• No silent data loss — either code reaches main or error is clearly reported
• Build passes: npm run build

[xliry]

Plan

• Replace the silent push-failure return in mergeWorktree() with a retry loop (max 3 attempts)
• On each push failure: git reset --hard HEAD~1 → git pull --ff-only origin main → git merge <branch> --no-edit → retry push
• Log each retry attempt to stdout
• If all 3 retries fail, return success: false with a clear error message including attempt count
• File: src/worktree.ts, lines ~135–145
• Run npm run build to verify no regressions

[xliry]

Completion Report

Added a 3-attempt retry loop in mergeWorktree() to fix the TOCTOU push race condition. On push failure, the loop: resets the merge (git reset --hard HEAD~1), pulls latest main (git pull --ff-only), re-merges the branch, and retries the push. Logs each attempt. Returns a clear error after all retries are exhausted. Build passes.

Modified: src/worktree.ts