feat(ws): 新增WebSocket实时通信支持与SSE独立服务

重构中间件结构，新增ws模块实现WebSocket流程执行实时推送
将SSE服务拆分为独立端口监听，默认8866
优化前端流式模式切换，支持WS/SSE协议选择
统一流式事件处理逻辑，完善错误处理与取消机制
更新Cargo.toml依赖，添加WebSocket相关库
调整代码组织结构，规范导入分组与注释

backend/src/routes/flows.rs

@@ -1,11 +1,27 @@
-use axum::{Router, routing::{post, get}, extract::{State, Path, Query}, Json};
-use crate::{db::Db, response::ApiResponse, services::{flow_service, log_service}, error::AppError};
-use serde::Deserialize;
-use tracing::{info, error};
-use crate::middlewares::jwt::AuthUser;
+// axum
+use axum::extract::{Path, Query, State, ws::WebSocketUpgrade};
+use axum::http::HeaderMap;
+use axum::response::Response;
+use axum::routing::{get, post};
+use axum::{Json, Router};
 
+// std
+use std::collections::HashMap;
+
+// third-party
+use serde::Deserialize;
+use tracing::{error, info};
+
+// crate
+use crate::middlewares::jwt::AuthUser;
 // 新增：引入通用 SSE 组件
 use crate::middlewares::sse;
+use crate::{
+    db::Db,
+    error::AppError,
+    response::ApiResponse,
+    services::{flow_service, log_service},
+};
 
 pub fn router() -> Router<Db> {
   Router::new()
@@ -14,6 +30,14 @@ pub fn router() -> Router<Db> {
     .route("/flows/{id}/run", post(run))
     // 新增：流式运行（SSE）端点
     .route("/flows/{id}/run/stream", post(run_stream))
+    // 新增：WebSocket 实时输出端点（GET 握手）
+    .route("/flows/{id}/run/ws", get(run_ws))
+}
+
+// 新增：仅包含 WS 路由的精简 router，便于在单独端口挂载
+pub fn ws_router() -> Router<Db> {
+  Router::new()
+    .route("/flows/{id}/run/ws", get(run_ws))
 }
 
 #[derive(Deserialize)]
@@ -106,4 +130,16 @@ async fn run_stream(State(db): State<Db>, user: AuthUser, Path(id): Path<String>
 
   // 由通用组件把 Receiver 包装为 SSE 响应
   Ok(sse::from_mpsc(rx))
+}
+
+// ================= WebSocket 模式：路由仅做转发 =================
+
+async fn run_ws(
+  State(db): State<Db>,
+  Path(id): Path<String>,
+  Query(q): Query<HashMap<String, String>>,
+  headers: HeaderMap,
+  ws: WebSocketUpgrade,
+) -> Result<Response, AppError> {
+  crate::middlewares::ws::run_ws(State(db), Path(id), Query(q), headers, ws).await
 }