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.

Modules/lvgl-module/Include/tactility/lvgl_module.h

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: Apache-2.0
+#pragma once
+
+/**
+ * @file lvgl_module.h
+ * @brief LVGL module for Tactility.
+ *
+ * This module manages the lifecycle of the LVGL library, including initialization,
+ * task management, and thread-safety.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/**
+ * @brief The LVGL module instance.
+ */
+extern struct Module lvgl_module;
+
+/**
+ * @brief Configuration for the LVGL module.
+ */
+struct LvglModuleConfig {
+    /**
+     * @brief Callback invoked when the LVGL task starts.
+     * Use this to add devices (e.g. displays, pointers), start services, create widgets, etc.
+     */
+    void (*on_start)(void);
+
+    /**
+     * @brief Callback invoked when the LVGL task stops.
+     * Use this to remove devices, stop services, etc.
+     */
+    void (*on_stop)(void);
+
+    /** @brief Priority of the LVGL task. */
+    int task_priority;
+
+    /** @brief Stack size of the LVGL task in bytes. */
+    int task_stack_size;
+
+#ifdef ESP_PLATFORM
+    /** @brief CPU affinity of the LVGL task (ESP32 specific). */
+    int task_affinity;
+#endif
+};
+
+/**
+ * @brief Configures the LVGL module.
+ *
+ * @warning This must be called before starting the module.
+ * @param config The configuration to apply.
+ */
+void lvgl_module_configure(struct LvglModuleConfig config);
+
+/**
+ * @brief Locks the LVGL mutex.
+ *
+ * This should be called before any LVGL API calls from threads other than the LVGL task.
+ * It is a recursive mutex.
+ * @retval true when a lock was acquired, false otherwise
+ */
+bool lvgl_lock(void);
+
+/**
+ * @brief Tries to lock the LVGL mutex with a timeout.
+ *
+ * @param timeout Timeout in ticks
+ * @return true if the lock was acquired, false otherwise.
+ */
+bool lvgl_try_lock_timed(uint32_t timeout);
+
+/**
+ * @brief Unlocks the LVGL mutex.
+ */
+void lvgl_unlock(void);
+
+/**
+ * @brief Checks if the LVGL module is currently running.
+ *
+ * @return true if running, false otherwise.
+ */
+bool lvgl_is_running();
+
+#ifdef __cplusplus
+}
+#endif