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.

Platforms/PlatformPosix/Source/freertos.c

@@ -0,0 +1,20 @@
+#include <stdlib.h>
+#if defined(__GLIBC__)
+#include <assert.h>
+#endif
+#include <tactility/freertos/task.h>
+#include <tactility/log.h>
+
+#define TAG LOG_TAG(freertos)
+
+/**
+ * Assert implementation as defined in the FreeRTOSConfig.h
+ */
+void vAssertCalled(unsigned long line, const char* const file) {
+    LOG_E("Assert triggered at {}:{}", file, line);
+#if defined(__GLIBC__)
+    __assert_fail("assert failed", file, line, "");
+#else
+    abort();
+#endif
+}