feat: 添加编译时模块开关配置

通过 sdkconfig.defaults 选择性启用/禁用模块，减少固件体积：

新增模块开关：
- CONFIG_MIMI_CHAN_TELEGRAM (默认 n)
- CONFIG_MIMI_CHAN_FEISHU (默认 y)
- CONFIG_MIMI_TOOL_WEB_SEARCH (默认 y)
- CONFIG_MIMI_TOOL_GPIO (默认 n)
- CONFIG_MIMI_WS_SERVER (默认 y)
- CONFIG_MIMI_WIFI_ONBOARD (默认 y)
- CONFIG_MIMI_OTA (默认 n)

技术实现：
- CMakeLists.txt 条件编译源文件
- 头文件使用 static inline stub
- CLI 命令和工具注册也支持条件编译

消除 Telegram 未配置时的 5 秒轮询警告日志

main/channels/feishu/feishu_bot.h

@@ -2,35 +2,25 @@
 
 #include "esp_err.h"
 
-/**
- * Initialize the Feishu bot (load credentials from NVS / build-time).
- */
+#ifdef CONFIG_MIMI_CHAN_FEISHU
 esp_err_t feishu_bot_init(void);
-
-/**
- * Start the Feishu webhook HTTP server for receiving events.
- * Listens on MIMI_FEISHU_WEBHOOK_PORT.
- */
 esp_err_t feishu_bot_start(void);
-
-/**
- * Send a text message to a Feishu chat.
- * Automatically splits messages longer than MIMI_FEISHU_MAX_MSG_LEN chars.
- * @param chat_id  Feishu chat ID (open_id or chat_id)
- * @param text     Message text
- */
 esp_err_t feishu_send_message(const char *chat_id, const char *text);
-
-/**
- * Reply to a specific message in a Feishu chat.
- * @param message_id  The message_id to reply to
- * @param text        Reply text
- */
 esp_err_t feishu_reply_message(const char *message_id, const char *text);
-
-/**
- * Save Feishu app credentials to NVS.
- * @param app_id     Feishu App ID
- * @param app_secret Feishu App Secret
- */
 esp_err_t feishu_set_credentials(const char *app_id, const char *app_secret);
+#else
+static inline esp_err_t feishu_bot_init(void) { return ESP_OK; }
+static inline esp_err_t feishu_bot_start(void) { return ESP_OK; }
+static inline esp_err_t feishu_send_message(const char *chat_id, const char *text) {
+    (void)chat_id; (void)text;
+    return ESP_OK;
+}
+static inline esp_err_t feishu_reply_message(const char *message_id, const char *text) {
+    (void)message_id; (void)text;
+    return ESP_OK;
+}
+static inline esp_err_t feishu_set_credentials(const char *app_id, const char *app_secret) {
+    (void)app_id; (void)app_secret;
+    return ESP_OK;
+}
+#endif

main/channels/telegram/telegram_bot.h

@@ -2,26 +2,20 @@
 
 #include "esp_err.h"
 
-/**
- * Initialize the Telegram bot.
- */
+#ifdef CONFIG_MIMI_CHAN_TELEGRAM
 esp_err_t telegram_bot_init(void);
-
-/**
- * Start the Telegram polling task (long polling on Core 0).
- */
 esp_err_t telegram_bot_start(void);
-
-/**
- * Send a text message to a Telegram chat.
- * Automatically splits messages longer than 4096 chars.
- * @param chat_id  Telegram chat ID (numeric string)
- * @param text     Message text (supports Markdown)
- */
 esp_err_t telegram_send_message(const char *chat_id, const char *text);
-
-/**
- * Save the Telegram bot token to NVS.
- */
 esp_err_t telegram_set_token(const char *token);
-
+#else
+static inline esp_err_t telegram_bot_init(void) { return ESP_OK; }
+static inline esp_err_t telegram_bot_start(void) { return ESP_OK; }
+static inline esp_err_t telegram_send_message(const char *chat_id, const char *text) {
+    (void)chat_id; (void)text;
+    return ESP_OK;
+}
+static inline esp_err_t telegram_set_token(const char *token) {
+    (void)token;
+    return ESP_OK;
+}
+#endif