iOS PWA runs stale builds until reinstalled — ship in-place auto-update + verify on device

[EnesYilmazcode]

Problem

The app is configured with registerType: 'autoUpdate' (vite.config.js), but on iOS a home-screen PWA is frozen and resumed rather than genuinely relaunched, so Safari's built-in service-worker update check rarely fires. Result: the phone keeps running an old build for days, and the current workaround (delete the icon → re-add to home screen) is dangerous — deleting the icon can drop the origin's IndexedDB, which holds every imported song, playlist, and star (src/lib/db.js, audioBlobs store).

Fix (implemented on branch claude/phone-app-auto-update-xgckp7)

• src/lib/pwa.js: registers the SW via virtual:pwa-register and calls registration.update() on every return to foreground (visibilitychange → visible) plus hourly while open. With autoUpdate, a detected new build activates and reloads on its own.
• src/main.jsx: calls requestPersistentStorage() at startup (previously only on import) so iOS is asked to mark the library durable every launch.
• Hidden version readout to confirm updates actually land: long-press the tab bar → small pill with build <commit> · <date> <time> (stamped at build time via a Vite define), auto-hides after 5 s. Invisible in normal use.

Remaining work

• Merge the branch and deploy (npm run deploy:sparky)
• On the phone: open the installed app once with network, background it, wait for the next deploy, then reopen and long-press the tab bar — the commit hash should match the new deploy within one foreground cycle (worst case two: one to fetch, one to activate)
• If activation lags, consider showing a subtle "restart to update" affordance or calling skipWaiting explicitly
• Document in README: never remove/re-add the icon; to force-refresh, swipe the app away in the app switcher and reopen

Acceptance criteria

A new deploy is running on the phone within one open→close→open cycle, with zero manual steps and zero data loss.