Updater heals itself: PM2 cron revived, Update now, failure reasons

PM2's cron for autofirmer-update dies inside a live daemon (six Windows
machines in October), and nothing on the machine noticed. The app now
watches scripts/.last-check and, past 10 minutes, runs
update-check.mjs --heal: a checker PM2 still lists is restarted (which
re-registers its cron), one it lost is registered again, and one whose
errored entry still holds a live pid is left alone, since PM2 would kill
that pid. The heal scrubs PM2's per-app fields from its environment first.

The master's new 'update-now' command runs --heal --now, skipping a
failed update's retry wait. A failed pull, npm install or build records
one line of reason (or the chown to run when a file isn't ours), which
rides on .last-check to the master. A package-lock.json rewritten by npm
is put back before the pull. The fetch timeout drops under the cron's
minute. scripts/.no-auto-update opts a checkout out.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -63,6 +63,8 @@ scripts/update.log
 scripts/.built-commit
 scripts/.update-failed
 scripts/update-worker.log
+# present = this checkout is never auto-updated or healed (a dev checkout)
+scripts/.no-auto-update
 # the previous build, set aside while the updater builds (Tailwind's source
 # scan also honours this, so it never reads the old bundles)
 /.next-prev/