Add theme management and background rendering features

- Introduced a comprehensive theme management system, allowing users to load, save, and switch between multiple themes.
- Added support for various built-in themes, enhancing the visual customization of the application.
- Implemented a background renderer for improved visual effects in docking windows, including grid backgrounds and subtle animations.
- Enhanced the EditorManager UI with themed elements, providing a more cohesive and engaging user experience.
- Updated CMake configuration to include new theme and background renderer source files, ensuring proper integration into the build system.

src/app/core/controller.cc

@@ -5,6 +5,8 @@
 #include "absl/status/status.h"
 #include "app/core/window.h"
 #include "app/editor/editor_manager.h"
+#include "app/gui/background_renderer.h"
+#include "app/gui/theme_manager.h"
 #include "imgui/backends/imgui_impl_sdl2.h"
 #include "imgui/backends/imgui_impl_sdlrenderer2.h"
 #include "imgui/imgui.h"
@@ -54,10 +56,10 @@ absl::Status Controller::OnLoad() {
   ImGui::Begin("DockSpaceWindow", nullptr, window_flags);
   ImGui::PopStyleVar(3);
 
-  // Create DockSpace
+  // Create DockSpace first
   ImGuiID dockspace_id = ImGui::GetID("MyDockSpace");
-  ImGui::DockSpace(dockspace_id, ImVec2(0.0f, 0.0f),
-                   ImGuiDockNodeFlags_PassthruCentralNode);
+  gui::DockSpaceRenderer::BeginEnhancedDockSpace(dockspace_id, ImVec2(0.0f, 0.0f),
+                                                 ImGuiDockNodeFlags_PassthruCentralNode);
 
   editor_manager_.DrawMenuBar();  // Draw the fixed menu bar at the top
 

src/app/core/platform/file_dialog.cc

@@ -78,6 +78,19 @@ void SaveFile(const std::string &filename, const std::string &contents) {
   }
 }
 
+std::string GetResourcePath(const std::string &resource_path) {
+#ifdef __APPLE__
+#if TARGET_OS_IOS == 1
+  const std::string kBundlePath = GetBundleResourcePath();
+  return kBundlePath + resource_path;
+#else
+  return GetBundleResourcePath() + "Contents/Resources/" + resource_path;
+#endif
+#else
+  return resource_path;  // On Linux/Windows, resources are relative to executable
+#endif
+}
+
 std::string GetConfigDirectory() {
   std::string config_directory = ".yaze";
   Platform platform;

src/app/core/platform/file_dialog.h

@@ -45,6 +45,7 @@ std::string GetFileName(const std::string &filename);
 std::string LoadFile(const std::string &filename);
 std::string LoadConfigFile(const std::string &filename);
 std::string GetConfigDirectory();
+std::string GetResourcePath(const std::string &resource_path);
 void SaveFile(const std::string &filename, const std::string &data);
 
 }  // namespace core

src/app/core/window.cc

@@ -6,7 +6,9 @@
 #include "app/core/platform/sdl_deleter.h"
 #include "app/gfx/arena.h"
 #include "app/gui/style.h"
+#include "app/gui/theme_manager.h"
 #include "app/test/test_manager.h"
+#include "util/log.h"
 #include "imgui/backends/imgui_impl_sdl2.h"
 #include "imgui/backends/imgui_impl_sdlrenderer2.h"
 #include "imgui/imgui.h"
@@ -49,7 +51,16 @@ absl::Status CreateWindow(Window& window, int flags) {
 
   RETURN_IF_ERROR(LoadPackageFonts());
 
+  // Apply original YAZE colors as fallback, then try to load theme system
   gui::ColorsYaze();
+  
+  // Try to initialize theme system (will fallback to ColorsYaze if files fail)
+  auto& theme_manager = gui::ThemeManager::Get();
+  auto status = theme_manager.LoadTheme("YAZE Classic");
+  if (!status.ok()) {
+    // Theme system failed, stick with original ColorsYaze()
+    util::logf("Theme system failed, using original ColorsYaze(): %s", status.message().data());
+  }
 
   const int audio_frequency = 48000;
   SDL_AudioSpec want, have;