Refactor LVGL code into kernel module (#472)

* **New Features**
  * Added a standalone LVGL module and enabled LVGL support in the simulator for richer local UI testing.

* **Refactor**
  * HAL and LVGL split into distinct modules; startup and device attach/detach flows reorganized for clearer lifecycle management.
  * Public APIs tightened with clearer nullability/documentation.

* **Bug Fixes**
  * More consistent LVGL start/stop and device attach/detach behavior for improved stability.

Tactility/Source/app/AppRegistration.cpp

@@ -39,7 +39,7 @@ bool removeAppManifest(const std::string& id) {
     return app_manifest_map.erase(id) == 1;
 }
 
-_Nullable std::shared_ptr<AppManifest> findAppManifestById(const std::string& id) {
+std::shared_ptr<AppManifest> findAppManifestById(const std::string& id) {
     hash_mutex.lock();
     auto result = app_manifest_map.find(id);
     hash_mutex.unlock();