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.

Drivers/ILI934x/Source/Ili934xDisplay.h

@@ -25,7 +25,7 @@ public:
         bool swapBytes;
         uint32_t bufferSize; // Pixel count, not byte count. Set to 0 for default (1/10th of display size)
         std::shared_ptr<tt::hal::touch::TouchDevice> touch;
-        std::function<void(uint8_t)> _Nullable backlightDutyFunction;
+        std::function<void(uint8_t)> backlightDutyFunction; // Nullable
         gpio_num_t resetPin;
         lcd_rgb_element_order_t rgbElementOrder;
     };