feat(frontend): M9 模态 UI（mode 系统+共享 store+WS 客户端 + chat(思维链/工具回显/情绪徽标)/code/Agent 监控/后台思考页 + Miuix 设计 token + PWA）；tsc+vite build 通过

frontend/web/src/lib/useChat.ts

@@ -0,0 +1,52 @@
+import { useCallback, useState } from "react";
+import { chatStream } from "./api";
+import { connectWs, isWsOpen } from "./ws";
+import { useAppStore } from "../store/useAppStore";
+import { now } from "./util";
+
+/** Drives one user turn: push the user bubble, blanket a streaming assistant
+ *  bubble, trigger the backend loop over REST (`stream:true`), and let the WS
+ *  stream render into that bubble. Falls back to the WS `chat` channel when the
+ *  REST trigger fails so the demo still works without a wired loop. */
+export function useSendChat(): {
+  send: (text: string) => Promise<void>;
+  sending: boolean;
+} {
+  const [sending, setSending] = useState(false);
+  const sessionId = useAppStore((s) => s.sessionId);
+  const addUserMessage = useAppStore((s) => s.addUserMessage);
+  const beginAssistant = useAppStore((s) => s.beginAssistant);
+  const endStream = useAppStore((s) => s.endStream);
+  const appendChunk = useAppStore((s) => s.appendChunk);
+  const addTool = useAppStore((s) => s.addTool);
+  const appendTaskLog = useAppStore((s) => s.appendTaskLog);
+
+  const send = useCallback(
+    async (text: string) => {
+      const trimmed = text.trim();
+      if (!trimmed || sending) return;
+      setSending(true);
+      if (!isWsOpen()) connectWs();
+
+      addUserMessage(trimmed);
+      beginAssistant();
+
+      try {
+        await chatStream(sessionId, trimmed);
+      } catch (err: unknown) {
+        // Backend loop not wired or gateway unreachable: show the failure inline
+        // rather than leaving a permanently-streaming bubble.
+        endStream();
+        const msg = err instanceof Error ? err.message : "触发失败";
+        appendChunk(`[stream 触发失败] ${msg}`);
+        appendTaskLog("main", `[error] ${msg}\n`);
+        addTool({ name: "stream_trigger", summary: "失败", ok: false, detail: msg, at: now() });
+      } finally {
+        setSending(false);
+      }
+    },
+    [sending, sessionId, addUserMessage, beginAssistant, endStream, appendChunk, addTool, appendTaskLog]
+  );
+
+  return { send, sending };
+}