AI-2146: fix stale notes.md and silent permission errors in init_task_record.py

[RachelXiaolan]

What this fixes

scripts/init_task_record.py had two related footguns when run twice on the same issue id (or when --root pointed at a read-only directory):

1. Stale notes.md. A second run with new --title / --repo / --branch would rewrite task.json while preserving notes.md from the previous issue. The result was a folder whose task.json (title, repo, branch) and notes.md (Scope, Progress, Links) disagreed about which Linear issue they belonged to.
2. Silent crash on permission errors. Path.mkdir(parents=True, exist_ok=True) swallows FileExistsError but lets PermissionError propagate as a raw traceback, with no actionable hint and a partial folder left behind.

Changes

• Refuse to create a task artifact in an existing folder unless --force is passed (exit code 2, clear stderr message).
• --force reuses the folder and rewrites both task.json and notes.md atomically so they always describe the same issue.
• PermissionError / generic OSError from mkdir are caught and turned into a clean non-zero exit with an actionable message; no partial folders are left behind.

Tests

tests/test_init_task_record.py covers:

• First-run creation of both task.json and notes.md.
• Repeat-run refusal: notes.md and task.json preserved unchanged.
• --force refresh: both files rewritten atomically.
• Permission-error: non-zero exit, no partial folder, clean stderr.

$ python3 tests/test_init_task_record.py
  ✅ test_first_run_creates_both_files
  ✅ test_repeat_run_refuses_without_force
  ✅ test_force_overwrites_atomically
  ✅ test_permission_error_exits_cleanly
4 passed, 0 failed

Linear

Tracked under AI-2146 (parent AI-2145). No code behavior change for the existing happy path — only the failure / repeat-run cases are tightened.

[RachelXiaolan]

🔗 Synced from Linear

• Linear: AI-2146 (parent: AI-2145)
• GitHub mirror issue: AI-2146: fix stale notes.md and silent permission errors in init_task_record.py #8

🤖 Codex