feat: Introduce UI Helper Functions and Refactor Color Management

- Added ui_helpers.cc and ui_helpers.h to centralize UI-related helper functions, improving code organization and reducing boilerplate in ImGui usage.
- Refactored color management in BppFormatUI to utilize new helper functions for success, warning, and error colors, enhancing theming consistency.
- Updated AgentChatWidget and CanvasContextMenu to streamline UI rendering and improve maintainability by removing redundant code and enhancing functionality.
- Removed canvas_utils_moved.cc and canvas_utils_moved.h to clean up the project structure, consolidating utility functions into more appropriate locations.

src/app/gui/widgets/palette_widget.h

@@ -69,10 +69,10 @@ public:
   bool IsROMLoaded() const { return rom_ != nullptr; }
   int GetCurrentGroupIndex() const { return current_group_index_; }
   int GetCurrentPaletteIndex() const { return current_palette_index_; }
-  
+  void DrawROMPaletteSelector();
+ 
 private:
   void DrawPaletteGrid(gfx::SnesPalette& palette, int cols = 8);
-  void DrawROMPaletteSelector();
   void DrawColorEditControls(gfx::SnesColor& color, int color_index);
   void DrawPaletteAnalysis(const gfx::SnesPalette& palette);
   void LoadROMPalettes();