PWA for iPhone and iPad: PNG icons, splash screens, manifest; stay signed in for 180 days

- iOS ignores SVG touch icons: add 120/152/167/180 apple-touch-icons, 192/512 and maskable manifest icons,
  and 25 splash screens (every iPhone size, iPad portrait+landscape incl. 12.9")
- Icons and splash screens are public so iOS can fetch them without a session
- Manifest: id, scope, categories, shortcuts; iOS standalone polish (no callout, no overscroll)
- Sessions last SESSION_DAYS (default 180) and renew daily while in use
- tools/make-icons.py regenerates the artwork

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

.env.example

@@ -11,3 +11,5 @@ AUDIOBOOKS_URL=https://audiobooks.necloud.us
 HUB_SETUP_CODE=
 VERSE_URL=https://versebyversewithnate.us/admin
 PODCAST_URL=https://podcast.necloud.us/
+# Days you stay signed in without using the app (it renews every time you do)
+SESSION_DAYS=180