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/cli/serial_cli.c

@@ -1012,6 +1012,7 @@ esp_err_t serial_cli_init(void)
     esp_console_cmd_register(&wifi_scan_cmd);
 
     /* set_tg_token */
+#ifdef CONFIG_MIMI_CHAN_TELEGRAM
     tg_token_args.token = arg_str1(NULL, NULL, "<token>", "Telegram bot token");
     tg_token_args.end = arg_end(1);
     esp_console_cmd_t tg_token_cmd = {
@@ -1021,8 +1022,13 @@ esp_err_t serial_cli_init(void)
         .argtable = &tg_token_args,
     };
     esp_console_cmd_register(&tg_token_cmd);
+#else
+    (void)cmd_set_tg_token;
+    (void)tg_token_args;
+#endif
 
     /* set_feishu_creds */
+#ifdef CONFIG_MIMI_CHAN_FEISHU
     feishu_creds_args.app_id = arg_str1(NULL, NULL, "<app_id>", "Feishu App ID");
     feishu_creds_args.app_secret = arg_str1(NULL, NULL, "<app_secret>", "Feishu App Secret");
     feishu_creds_args.end = arg_end(2);
@@ -1045,6 +1051,12 @@ esp_err_t serial_cli_init(void)
         .argtable = &feishu_send_args,
     };
     esp_console_cmd_register(&feishu_send_cmd);
+#else
+    (void)cmd_set_feishu_creds;
+    (void)cmd_feishu_send;
+    (void)feishu_creds_args;
+    (void)feishu_send_args;
+#endif
 
     /* set_api_key */
     api_key_args.key = arg_str1(NULL, NULL, "<key>", "LLM API key");
@@ -1200,6 +1212,7 @@ esp_err_t serial_cli_init(void)
     esp_console_cmd_register(&heap_cmd);
 
     /* set_search_key */
+#ifdef CONFIG_MIMI_TOOL_WEB_SEARCH
     search_key_args.key = arg_str1(NULL, NULL, "<key>", "Brave Search API key");
     search_key_args.end = arg_end(1);
     esp_console_cmd_t search_key_cmd = {
@@ -1220,6 +1233,12 @@ esp_err_t serial_cli_init(void)
         .argtable = &tavily_key_args,
     };
     esp_console_cmd_register(&tavily_key_cmd);
+#else
+    (void)cmd_set_search_key;
+    (void)cmd_set_tavily_key;
+    (void)search_key_args;
+    (void)tavily_key_args;
+#endif
 
     /* set_proxy */
     proxy_args.host = arg_str1(NULL, NULL, "<host>", "Proxy host/IP");
@@ -1302,6 +1321,7 @@ esp_err_t serial_cli_init(void)
     esp_console_cmd_register(&tool_exec_cmd);
 
     /* web_search */
+#ifdef CONFIG_MIMI_TOOL_WEB_SEARCH
     web_search_args.query = arg_str1(NULL, NULL, "<query>", "Search query");
     web_search_args.end = arg_end(1);
     esp_console_cmd_t web_search_cmd = {
@@ -1311,6 +1331,10 @@ esp_err_t serial_cli_init(void)
         .argtable = &web_search_args,
     };
     esp_console_cmd_register(&web_search_cmd);
+#else
+    (void)cmd_web_search;
+    (void)web_search_args;
+#endif
 
     /* restart */
     esp_console_cmd_t restart_cmd = {