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/llm/mod.rs

@@ -453,6 +453,7 @@ impl EmbeddingClient {
     }
 }
 
+// @reserved: embedding vector generation
 // @connected
 #[tauri::command]
 pub async fn embedding_create(
@@ -473,6 +474,7 @@ pub async fn embedding_create(
     client.embed(&text).await
 }
 
+// @reserved: embedding provider listing
 // @connected
 #[tauri::command]
 pub async fn embedding_providers() -> Result<Vec<(String, String, String, usize)>, String> {