iPad and Screen Time helper; v2.0 roadmap

- Admin screen: the simple Screen Time setup, the web addresses the app needs, addresses devices were seen reaching, and a Check this device test
- Report-only Content-Security-Policy so devices report any other address a page loads (nothing is blocked)
- Pictures from other sites pass through the hub (/api/img): podcast search covers, Plex Home pictures, a VBV cover, search answers
- docs/v2-roadmap.md: the family-first 2.0 plan, with Family Chat (text only) and no photos or calls

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

public/sw.js

@@ -1,5 +1,5 @@
 // App-shell cache only; Seafile/API traffic always goes to the network.
-const CACHE = 'hub-v57';
+const CACHE = 'hub-v58';
 const SHARE = 'hub-share'; // files shared into the app from other apps, held until the person picks a folder
 const SHELL = ['/icon.svg', '/manifest.webmanifest', '/icons/icon-192.png', '/icons/apple-touch-icon.png'];