feat(display): 集成LVGL图形库并重构显示模块

- 将display_test_module重命名为display_module
- 集成LVGL配置到prj.conf中，包括颜色深度、双缓冲等设置
- 添加UI主界面实现(ui_main.c)，包含标题和副标题显示
- 实现背光控制功能替代原有的测试图案绘制
- 调整LCD配置参数(mdac从0x70改为0xA0)
- 修改日志级别从DEBUG降至ERROR以优化性能
- 在CMakeLists.txt中添加UI模块源文件引用

src/ui/ui_main.c

@@ -0,0 +1,34 @@
+#include <stdbool.h>
+
+#include <lvgl.h>
+
+#include "ui_main.h"
+
+static bool ui_initialized;
+
+void ui_main_init(void)
+{
+	lv_obj_t *screen;
+	lv_obj_t *title;
+	lv_obj_t *subtitle;
+
+	if (ui_initialized) {
+		return;
+	}
+
+	screen = lv_screen_active();
+	lv_obj_set_style_bg_color(screen, lv_color_hex(0x101418), 0);
+	lv_obj_set_style_text_color(screen, lv_color_hex(0xF5F7FA), 0);
+
+	title = lv_label_create(screen);
+	lv_label_set_text(title, "Hello World");
+	lv_obj_set_style_text_font(title, &lv_font_montserrat_14, 0);
+	lv_obj_align(title, LV_ALIGN_CENTER, 0, -10);
+
+	subtitle = lv_label_create(screen);
+	lv_label_set_text(subtitle, "WH Mini Keyboard");
+	lv_obj_set_style_text_opa(subtitle, LV_OPA_70, 0);
+	lv_obj_align(subtitle, LV_ALIGN_CENTER, 0, 14);
+
+	ui_initialized = true;
+}

src/ui/ui_main.h

@@ -0,0 +1,14 @@
+#ifndef BLINKY_UI_MAIN_H_
+#define BLINKY_UI_MAIN_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void ui_main_init(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* BLINKY_UI_MAIN_H_ */