Add Persian (fa) localization and an in-app language picker (#1443)

* Add Persian (fa) localization and an in-app language picker

Persian was the one notable gap in the 29-language catalog. Translate all
381 strings (plus the share extension) with proper plural substitutions,
and register fa in knownRegions.

Settings gains a LANGUAGE section: a picker over every language the bundle
ships (native names via Locale), backed by an AppleLanguages override so
users can run bitchat in a language different from the device's. Localization
resolves at process start, so the picker surfaces a restart note.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Remove unused AppLanguageSettings.currentOverride (Periphery)

AppInfoView reads the override via @AppStorage, so the accessor was dead
code and failed the Periphery CI scan.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: jack <jackjackbits@users.noreply.github.com>
Co-authored-by: jack <212554440+jackjackbits@users.noreply.github.com>

bitchat.xcodeproj/project.pbxproj

@@ -337,6 +337,7 @@
 				es,
 				ar,
 				de,
+				fa,
 				fr,
 				he,
 				id,