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_sk.dart

@@ -824,6 +824,45 @@ class AppLocalizationsSk extends AppLocalizations {
   @override
   String get channels_sortUnread => 'Nezriadené';
 
+  @override
+  String get channels_createPrivateChannel => 'Vytvorte súkromný kanál';
+
+  @override
+  String get channels_createPrivateChannelDesc =>
+      'Zabezpečené pomocou tajného kľúča.';
+
+  @override
+  String get channels_joinPrivateChannel => 'Pripojiť sa k súkromnému kanálu';
+
+  @override
+  String get channels_joinPrivateChannelDesc => 'Ručne zadajte tajný kľúč.';
+
+  @override
+  String get channels_joinPublicChannel => 'Pripojte sa k verejnému kanálu';
+
+  @override
+  String get channels_joinPublicChannelDesc =>
+      'Któvek sátó na tutó kanalizovát.';
+
+  @override
+  String get channels_joinHashtagChannel => 'Pripojte sa k Hashtag Kanálu';
+
+  @override
+  String get channels_joinHashtagChannelDesc =>
+      'Ktoekolikoľvek sa môže pridať do hashtag kanálov.';
+
+  @override
+  String get channels_scanQrCode => 'Skenujte QR kód';
+
+  @override
+  String get channels_scanQrCodeComingSoon => 'Čoskoro';
+
+  @override
+  String get channels_enterHashtag => 'Zadajte hashtag';
+
+  @override
+  String get channels_hashtagHint => 'napr. #tím';
+
   @override
   String get chat_noMessages => 'Zatiaľ žiadne správy.';