fix(cron): re-validate stale cron-output entries before deletion #37721

[kyssta-exe]

Summary

Fixes #37721 — stale tracked.json entries with category: "cron-output" pointing to cron control-plane files (e.g. cron/jobs.json) could cause quick() to delete the live scheduler registry.

Root Cause

1. guess_category() on fork was missing the fix(cron): stop silent cron-job loss across update (disk-cleanup + snapshot restore) #34840 fix — it classified ALL cron/* paths as cron-output, not just cron/output/**.
2. quick() and dry_run() trusted the stored category without re-validating at delete time. Stale entries from before fix(cron): stop silent cron-job loss across update (disk-cleanup + snapshot restore) #34840 could carry category: "cron-output" for paths like cron/jobs.json.

Fix

• Fix guess_category(): Only classify cron/output/** as cron-output (matching the fix(cron): stop silent cron-job loss across update (disk-cleanup + snapshot restore) #34840 fix on main).
• Re-validate at delete time: In quick() and dry_run(), re-run guess_category() for cron-output entries. Stale entries that no longer match are skipped and removed from tracked.json.
• Defense-in-depth: Add _is_protected_cron_path() that blocks deletion of cron, cronjobs, jobs.json, and .tick.lock regardless of stored category.

Changes

• plugins/disk-cleanup/disk_cleanup.py: 3 fixes + new _is_protected_cron_path() helper
• tests/plugins/test_disk_cleanup_plugin.py: 5 new regression tests in TestStaleCronEntryMigration, 1 existing test updated

Test Results

All 43 tests pass (38 existing + 5 new regression tests).

[alt-glitch]

Duplicate of #37726 (earliest open fix for #37721, triaged first). Also competes with #37760. All three re-validate cron-output paths before disk-cleanup quick()/dry_run() deletes them. Consolidate on one.

[teknium1]

Merged via #39067 (commit 30412a9 on main). Your commit was cherry-picked with your authorship preserved in git log.

I dropped the guess_category() hunk during salvage since that fix already landed on main via #34840 — kept your genuinely-new contribution: the delete-time re-validation in quick()/dry_run() plus the _is_protected_cron_path() defense-in-depth guard, and all 5 of your regression tests.

Verified live: quick() against a stale tracked.json mislabeling cron/jobs.json as cron-output now preserves the registry intact while still cleaning genuine cron/output/ artifacts. Thanks for the fix and the clear root-cause writeup.