feat: add replay TTS audio button in WalkieTalkie and Conversation modes

[NikolaCavendish]

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Summary

Implemented manual TTS playback functionality for both WalkieTalkie and Conversation modes, allowing users to conveniently replay translated messages via a speaker icon. Integrated a precise cross-process onTTSDone callback mechanism for accurate UI state synchronization.

Details

• UI Enhancements: Added a speaker icon to each message bubble in WalkieTalkie and Conversation modes. Tweaked text containers with layout_weight="1" in component_message_send.xml and component_message_received.xml to prevent long translated texts from overlapping the icon.
• Precise IPC Callback: Introduced a new ON_TTS_DONE command in VoiceTranslationService. This implements a highly accurate native UtteranceProgressListener.onDone event propagation to keep the UI perfectly synchronized with the audio playback state.
• Utterance ID Tracking: Updated VoiceTranslationServiceCommunicator to attach a unique utteranceId (timestamp-based) during speakText calls. The UI correctly identifies the finished playback and resets the stop icon back to the play icon.
• Backward Compatibility: Maintained system stability by providing a default empty implementation of onTTSDone in the base VoiceTranslationServiceCallback, and safely overloaded the speak() method to prevent breaking existing auto-translation logic in WalkieTalkieService and ConversationService.

Other

None

[niedev]

Hi @NikolaCavendish, thank you very much for your contribution!
In the next days/weeks, I will review the PR.

[niedev]

Very good job! The only thing missing is the state management of the TTS inside the Service, but now I will do changes to the TTS logic, so it is better this way. I will directly implement the state management with the new logic, but this is a good base for everything else.
Now I will merge the PR, thank you again for your contribution!