Add support for private and hashtag channels in localization and channel management

- Updated Polish, Portuguese, Slovak, Slovenian, Swedish, and Chinese localization files to include new strings for creating and joining private channels, as well as joining hashtag channels.
- Enhanced the channel management UI to allow users to create and join private channels, join public channels, and join channels via hashtags.
- Implemented PSK derivation from hashtags using SHA256 in the Channel model.
- Improved the translation script to handle missing keys and translate all locales efficiently.

lib/l10n/app_localizations_bg.dart

@@ -830,6 +830,45 @@ class AppLocalizationsBg extends AppLocalizations {
   @override
   String get channels_sortUnread => 'Непрочетено';
 
+  @override
+  String get channels_createPrivateChannel => 'Създай Частен Канал';
+
+  @override
+  String get channels_createPrivateChannelDesc => 'Защитено с таен ключ.';
+
+  @override
+  String get channels_joinPrivateChannel => 'Присъедини се към Частен Канал';
+
+  @override
+  String get channels_joinPrivateChannelDesc => 'Ръчно въведете таен ключ.';
+
+  @override
+  String get channels_joinPublicChannel =>
+      'Присъединете се към Публичния канал';
+
+  @override
+  String get channels_joinPublicChannelDesc =>
+      'Всеки може да се присъедини към този канал.';
+
+  @override
+  String get channels_joinHashtagChannel => 'Присъедини се към Хаштаг Канал';
+
+  @override
+  String get channels_joinHashtagChannelDesc =>
+      'Всеки може да се присъедини към хаштаговите канали.';
+
+  @override
+  String get channels_scanQrCode => 'Сканирайте QR код';
+
+  @override
+  String get channels_scanQrCodeComingSoon => 'Ще излезе скоро';
+
+  @override
+  String get channels_enterHashtag => 'Въведете хаштаг';
+
+  @override
+  String get channels_hashtagHint => 'напр. #отбор';
+
   @override
   String get chat_noMessages => 'Няма съобщения.';