feat(keyboard): 添加LED模块支持

- 在CMakeLists.txt中添加src/modules/led_module.c源文件
- 创建app.overlay设备树配置文件，启用GPIO0、GPIO1、GPIOTE和LED_0
- 在prj.conf中启用CONFIG_GPIO配置选项
- 实现led_module.c，包含LED GPIO控制逻辑和CAF事件处理

CMakeLists.txt

@@ -3,4 +3,5 @@ find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 
 project(new_kbd)
 
-target_sources(app PRIVATE src/main.c)
+target_sources(app PRIVATE src/main.c
+                           src/modules/led_module.c)

app.overlay

@@ -0,0 +1,16 @@
+/{};
+&gpio0 {
+    status = "okay";
+};
+
+&gpio1 {
+    status = "okay";
+};
+
+&gpiote {
+    status = "okay";
+};
+
+&led_0 {
+    status = "okay";
+};

prj.conf

@@ -1,3 +1,4 @@
 CONFIG_CAF=y
 CONFIG_HEAP_MEM_POOL_SIZE=2048
 CONFIG_LOG=y
+CONFIG_GPIO=y

src/modules/led_module.c

@@ -0,0 +1,43 @@
+#include <app_event_manager.h>
+#define MODULE led
+#include <caf/events/module_state_event.h>
+
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(MODULE);
+
+static const struct gpio_dt_spec status_led = GPIO_DT_SPEC_GET(DT_PATH(led_0, chan0), gpios);
+
+static void led_module_start(void)
+{
+	if (!gpio_is_ready_dt(&status_led)) {
+		LOG_ERR("LED GPIO controller is not ready");
+		return;
+	}
+
+	int err = gpio_pin_configure_dt(&status_led, GPIO_OUTPUT_ACTIVE);
+	if (err) {
+		LOG_ERR("Failed to turn on LED (err: %d)", err);
+		return;
+	}
+
+	LOG_INF("LED is on");
+}
+
+static bool app_event_handler(const struct app_event_header *aeh)
+{
+	/* 仅处理 module_state_event，其他事件交给系统继续分发。 */
+	if (is_module_state_event(aeh)) {
+		const struct module_state_event *event = cast_module_state_event(aeh);
+
+		if (check_state(event, MODULE_ID(main), MODULE_STATE_READY)) {
+			led_module_start();
+		}
+	}
+
+	return false;
+}
+
+APP_EVENT_LISTENER(led_module, app_event_handler);
+APP_EVENT_SUBSCRIBE(led_module, module_state_event);
+