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.

CMakeLists.txt

@@ -123,6 +123,10 @@ endif()
 include(cmake/imgui.cmake)
 
 # Project Files
+# Copy theme files to build directory
+file(GLOB THEME_FILES "${CMAKE_SOURCE_DIR}/assets/themes/*.theme")
+file(COPY ${THEME_FILES} DESTINATION "${CMAKE_BINARY_DIR}/assets/themes/")
+
 add_subdirectory(src)
 
 # Tests