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.

Tests/TactilityKernel/Main.cpp

@@ -57,9 +57,3 @@ int main(int argc, char** argv) {
     return data.result;
 }
 
-extern "C" {
-    // Required for FreeRTOS
-    void vAssertCalled(unsigned long line, const char* const file) {
-        __assert_fail("assert failed", file, line, "");
-    }
-}