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/Include/Tactility/app/App.h

@@ -44,7 +44,8 @@ public:
     virtual void onDestroy(AppContext& appContext) {}
     virtual void onShow(AppContext& appContext, lv_obj_t* parent) {}
     virtual void onHide(AppContext& appContext) {}
-    virtual void onResult(AppContext& appContext, LaunchId launchId, Result result, std::unique_ptr<Bundle> _Nullable resultData) {}
+    /** resultData could be null */
+    virtual void onResult(AppContext& appContext, LaunchId launchId, Result result, std::unique_ptr<Bundle> resultData) {}
 
     Mutex& getMutex() { return mutex; }
 
@@ -81,9 +82,9 @@ std::shared_ptr<App> create() { return std::shared_ptr<T>(new T); }
 /**
  * @brief Start an app
  * @param[in] id application name or id
- * @param[in] parameters optional parameters to pass onto the application
+ * @param[in] parameters optional parameters to pass onto the application. can be nullptr.
  */
-LaunchId start(const std::string& id, std::shared_ptr<const Bundle> _Nullable parameters = nullptr);
+LaunchId start(const std::string& id, std::shared_ptr<const Bundle> parameters = nullptr);
 
 /** @brief Stop the currently showing app. Show the previous app if any app was still running. */
 void stop();
@@ -103,10 +104,10 @@ void stopAll(const std::string& id);
 bool isRunning(const std::string& id);
 
 /** @return the currently running app context (it is only ever null before the splash screen is shown) */
-std::shared_ptr<AppContext> _Nullable getCurrentAppContext();
+std::shared_ptr<AppContext> getCurrentAppContext();
 
 /** @return the currently running app (it is only ever null before the splash screen is shown) */
-std::shared_ptr<App> _Nullable getCurrentApp();
+std::shared_ptr<App> getCurrentApp();
 
 bool install(const std::string& path);
 

Tactility/Include/Tactility/app/AppRegistration.h

@@ -18,7 +18,7 @@ bool removeAppManifest(const std::string& id);
  * @param[in] id the manifest id
  * @return the application manifest if it was found
  */
-_Nullable std::shared_ptr<AppManifest> findAppManifestById(const std::string& id);
+std::shared_ptr<AppManifest> findAppManifestById(const std::string& id);
 
 /** @return a list of all registered apps. This includes user and system apps. */
 std::vector<std::shared_ptr<AppManifest>> getAppManifests();

Tactility/Include/Tactility/app/ElfApp.h

@@ -8,20 +8,26 @@ namespace tt::app {
 
 typedef void* (*CreateData)();
 typedef void (*DestroyData)(void* data);
-typedef void (*OnCreate)(void* appContext, void* _Nullable data);
-typedef void (*OnDestroy)(void* appContext, void* _Nullable data);
-typedef void (*OnShow)(void* appContext, void* _Nullable data, lv_obj_t* parent);
-typedef void (*OnHide)(void* appContext, void* _Nullable data);
-typedef void (*OnResult)(void* appContext, void* _Nullable data, LaunchId launchId, Result result, Bundle* resultData);
+/** data is nullable */
+typedef void (*OnCreate)(void* appContext, void* data);
+/** data is nullable */
+typedef void (*OnDestroy)(void* appContext, void* data);
+/** data is nullable */
+typedef void (*OnShow)(void* appContext, void* data, lv_obj_t* parent);
+/** data is nullable */
+typedef void (*OnHide)(void* appContext, void* data);
+/** data is nullable, resultData is nullable. */
+typedef void (*OnResult)(void* appContext, void* data, LaunchId launchId, Result result, Bundle* resultData);
 
+/** All fields are nullable */
 void setElfAppParameters(
-    CreateData _Nullable createData,
-    DestroyData _Nullable destroyData,
-    OnCreate _Nullable onCreate,
-    OnDestroy _Nullable onDestroy,
-    OnShow _Nullable onShow,
-    OnHide _Nullable onHide,
-    OnResult _Nullable onResult
+    CreateData createData,
+    DestroyData destroyData,
+    OnCreate onCreate,
+    OnDestroy onDestroy,
+    OnShow onShow,
+    OnHide onHide,
+    OnResult onResult
 );
 
 std::shared_ptr<App> createElfApp(const std::shared_ptr<AppManifest>& manifest);