Feature: Add Flutter Voice Selection UI and Platform Channels for DSP Control #684
Description
🚀 The feature
Add Flutter UI components for selecting predefined voice profiles and toggling preview mode.
Introduce platform channels to communicate user selections (e.g., selected voice profile, preview enabled/disabled) from Flutter to native code.
Flutter will strictly act as a control layer and will not process or handle audio buffers.
Motivation, pitch
Users need a simple and intuitive way to select voice styles before or during a session. Flutter is the appropriate layer for user interaction, while native code handles audio processing.
By keeping Flutter limited to UI and control signals via platform channels, we maintain real-time performance and avoid running audio logic in Dart. This preserves responsiveness and ensures clean separation between UI and audio processing.