refactor(emulator): enhance input handling and audio resampling features

- Renamed `turbo_mode()` to `is_turbo_mode()` for clarity in the Emulator class.
- Improved input handling in the Snes class by adding button state management and ensuring proper initialization of input controllers.
- Implemented multiple audio resampling methods (linear, cosine, cubic) in the Dsp class, allowing for enhanced audio quality during playback.
- Updated the user interface to include options for selecting audio interpolation methods and added keyboard shortcuts for emulator controls.

Benefits:
- Improved code readability and maintainability through clearer method naming and structured input management.
- Enhanced audio playback quality with new resampling techniques.
- Streamlined user experience with added UI features for audio settings and keyboard shortcuts.

src/app/emu/emulator.h

@@ -62,7 +62,7 @@ class Emulator {
   void* ppu_texture() { return ppu_texture_; }
   
   // Turbo mode
-  bool turbo_mode() const { return turbo_mode_; }
+  bool is_turbo_mode() const { return turbo_mode_; }
   void set_turbo_mode(bool turbo) { turbo_mode_ = turbo; }
   
   // Debugger access