fix(emu): link yaze_core_lib in emulator CMake configuration

- Added yaze_core_lib to the target_link_libraries for the yaze_emulator in emu_library.cmake, ensuring proper linkage of core functionalities.
- Updated Arena constructor to initialize background layers directly, improving clarity and performance.

Benefits:
- Enhances the emulator's build configuration by ensuring all necessary libraries are linked.
- Improves the initialization process in the Arena class for better resource management.

src/app/emu/emu_library.cmake

@@ -29,6 +29,7 @@ target_include_directories(yaze_emulator PUBLIC
 target_link_libraries(yaze_emulator PUBLIC
   yaze_util
   yaze_common
+  yaze_core_lib
   ${ABSL_TARGETS}
   ${SDL_TARGETS}
 )

src/app/gfx/resource/arena.cc

@@ -17,7 +17,7 @@ Arena& Arena::Get() {
   return instance;
 }
 
-Arena::Arena() {
+Arena::Arena() : bg1_(512, 512), bg2_(512, 512) {
   layer1_buffer_.fill(0);
   layer2_buffer_.fill(0);
 }