feat: Add Palette Editor for Enhanced Color Management

- Introduced a new PaletteEditorWidget for visual editing of dungeon palettes, allowing users to select and modify colors.
- Integrated palette editor into DungeonEditorV2, enabling real-time updates and re-rendering of rooms upon palette changes.
- Enhanced GUI layout to include a dedicated palette editor card, improving user experience and accessibility.
- Implemented callback functionality to notify when palette changes occur, ensuring seamless integration with room rendering.

src/app/editor/dungeon/dungeon_editor_v2.cc

@@ -50,6 +50,20 @@ absl::Status DungeonEditorV2::Load() {
 
   // NOW initialize emulator preview with loaded ROM
   object_emulator_preview_.Initialize(rom_);
+  
+  // Initialize palette editor with loaded ROM
+  palette_editor_.Initialize(rom_);
+  
+  // Wire palette changes to trigger room re-renders
+  palette_editor_.SetOnPaletteChanged([this](int palette_id) {
+    // Re-render all active rooms when palette changes
+    for (int i = 0; i < active_rooms_.Size; i++) {
+      int room_id = active_rooms_[i];
+      if (room_id >= 0 && room_id < (int)rooms_.size()) {
+        rooms_[room_id].RenderRoomGraphics();
+      }
+    }
+  });
 
   is_loaded_ = true;
   return absl::OkStatus();
@@ -134,8 +148,20 @@ void DungeonEditorV2::DrawLayout() {
     }
     object_card.End();
   }
+  
+  // 3. Palette Editor Card (independent, dockable)
+  {
+    static bool show_palette_editor = true;
+    gui::EditorCard palette_card(
+        MakeCardTitle("Palette Editor").c_str(), 
+        ICON_MD_PALETTE, &show_palette_editor);
+    if (palette_card.Begin()) {
+      palette_editor_.Draw();
+    }
+    palette_card.End();
+  }
 
-  // 3. Active Room Cards (independent, dockable, no inheritance)
+  // 4. Active Room Cards (independent, dockable, no inheritance)
   for (int i = 0; i < active_rooms_.Size; i++) {
     int room_id = active_rooms_[i];
     bool open = true;

src/app/editor/dungeon/dungeon_editor_v2.h

@@ -14,6 +14,7 @@
 #include "app/zelda3/dungeon/room_entrance.h"
 #include "app/gui/editor_layout.h"
 #include "app/gui/widgets/dungeon_object_emulator_preview.h"
+#include "app/gui/widgets/palette_editor_widget.h"
 #include "imgui/imgui.h"
 
 namespace yaze {
@@ -109,6 +110,7 @@ class DungeonEditorV2 : public Editor {
   DungeonCanvasViewer canvas_viewer_;
   DungeonObjectSelector object_selector_;
   gui::DungeonObjectEmulatorPreview object_emulator_preview_;
+  gui::PaletteEditorWidget palette_editor_;
   
   bool is_loaded_ = false;
 };