refactor: enhance localization support in chat and voice input features

- Integrated localization for various dialog messages and UI elements in the chat and voice input components.
- Updated the confirmation dialog to utilize localized strings for delete messages, improving user experience across different languages.
- Enhanced voice input sheet to reflect localized text for status updates, action buttons, and prompts, ensuring consistency in user interactions.
- Improved the file attachment widget to display the attachment label in a localized manner, enhancing accessibility for users in different regions.
- Streamlined localization management by centralizing string retrieval, promoting maintainability and clarity in the codebase.

lib/l10n/app_localizations_en.dart

@@ -400,12 +400,45 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get addAttachment => 'Add attachment';
 
+  @override
+  String get attachmentLabel => 'Attachment';
+
   @override
   String get tools => 'Tools';
 
   @override
   String get voiceInput => 'Voice input';
 
+  @override
+  String get voice => 'Voice';
+
+  @override
+  String get voiceStatusListening => 'Listening…';
+
+  @override
+  String get voiceStatusRecording => 'Recording…';
+
+  @override
+  String get voiceHoldToTalk => 'Hold to talk';
+
+  @override
+  String get voiceAutoSend => 'Auto-send';
+
+  @override
+  String get voiceTranscript => 'Transcript';
+
+  @override
+  String get voicePromptSpeakNow => 'Speak now…';
+
+  @override
+  String get voicePromptTapStart => 'Tap Start to begin';
+
+  @override
+  String get voiceActionStop => 'Stop';
+
+  @override
+  String get voiceActionStart => 'Start';
+
   @override
   String get messageInputLabel => 'Message input';
 
@@ -421,6 +454,9 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get send => 'Send';
 
+  @override
+  String get codeCopiedToClipboard => 'Code copied to clipboard.';
+
   @override
   String get sendMessage => 'Send message';
 
@@ -822,6 +858,16 @@ class AppLocalizationsEn extends AppLocalizations {
   String get quickActionsDescription =>
       'Pick up to two shortcuts to pin near the composer';
 
+  @override
+  String get chatSettings => 'Chat';
+
+  @override
+  String get sendOnEnter => 'Send on Enter';
+
+  @override
+  String get sendOnEnterDescription =>
+      'Enter sends (soft keyboard). Cmd/Ctrl+Enter also available';
+
   @override
   String get display => 'Display';