chore(desktop): Tauri 命令 @reserved 全量标注 — 88个无前端调用命令已标注

- 新增 66 个 @reserved 标注 (已有 22 个)
- 覆盖: agent/butler/classroom/hand/mcp/pipeline/skill/trigger/viking/zclaw 等模块
- MCP 命令增加 @connected 注释说明前端接入路径
- @reserved 总数: 89 (含 identity_init)

desktop/src-tauri/src/secure_storage.rs

@@ -32,6 +32,7 @@ pub fn secure_store_set(key: String, value: String) -> Result<(), String> {
 }
 
 /// Retrieve a value from the OS keyring
+// @reserved: secure storage access
 // @connected
 #[tauri::command]
 pub fn secure_store_get(key: String) -> Result<String, String> {
@@ -81,6 +82,7 @@ pub fn secure_store_delete(key: String) -> Result<(), String> {
 }
 
 /// Check if secure storage is available on this platform
+// @reserved: secure storage access
 // @connected
 #[tauri::command]
 pub fn secure_store_is_available() -> bool {