feat: Add Emulator Editor Type and UI Enhancements

- Introduced a new editor type for the emulator, allowing users to access emulator functionalities directly from the editor manager.
- Updated the editor selection dialog to include the emulator option with appropriate descriptions and shortcuts.
- Enhanced the emulator interface with modern theming and improved layout for better user experience.
- Implemented various UI components for performance monitoring, AI agent integration, and save state management, enriching the emulator's capabilities.

src/app/emu/video/ppu.cc

@@ -114,7 +114,7 @@ void Ppu::Reset() {
   fixed_color_g_ = 0;
   fixed_color_b_ = 0;
   forced_blank_ = true;
-  brightness = 0;
+  brightness = 15;  // SNES hardware default is maximum brightness
   mode = 0;
   bg3priority = false;
   even_frame = false;