Add offline reading, bookmarks, three UI languages and downloads

Reading
- Naskh is now the default face, and both Arabic-script fonts are registered
  at four weights so the text can be thickened for a lit screen.
- Category listings show each poem's opening line, fetched best-effort from
  api.ganjoor.net since the data set doesn't carry excerpts.
- Tap a couplet to save that passage or copy it; a saved passage keeps a
  tappable link back to its poem. Poem text is selectable for plain copying.

Languages
- Persian, Urdu and English, Persian by default whatever the phone's locale,
  applied in attachBaseContext and switchable from the top bar or the sheet.
- English chrome uses Libron (OFL); poems stay naskh or nastaliq throughout.
- Each language gets its own values-* folder: with Farsi only in values/,
  Android was resolving it to the Urdu strings, since a same-script locale
  outranks the default.

Offline
- Downloaded poets mirror the data set's layout under filesDir, so offline
  mode is one lookup rather than a parallel path. Downloads run one poet at
  a time, skip what's on disk, and resume by restarting.
- Downloads screen lists every poet with their portrait and tick boxes for
  picking several, plus storage used, delete, and download-everything behind
  a size warning.
- Offline mode refuses the network and says what's missing rather than
  blaming the connection.

Also: poet sort (Ganjoor's order or alphabetical, via a Persian collator),
RTL nav transitions, an original shamsa launcher icon with a monochrome layer
for themed icons, and preferences written with commit so they survive the
process being killed.

F-Droid: dependenciesInfo off, optional signing so the build works with no
keystore, fastlane metadata in three languages, cleartext traffic disabled.

Verified on an API 36 emulator: downloaded a poet, pulled the emulator's
network, read them offline, and confirmed an undownloaded poet reports being
missing rather than erroring.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/src/main/AndroidManifest.xml

@@ -12,6 +12,7 @@
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
+        android:usesCleartextTraffic="false"
         android:theme="@style/Theme.Ganjoorappandroid">
         <activity
             android:name=".MainActivity"