feat(blindbox): AI 计划生成流式进度与渐进式文案

- 新增 runPlanGeneration 与 onProgress 回调 (blindboxPlanGen.ts)
- 新增 POST /api/blindbox/plan/stream 推送 SSE 进度事件
- 前端优先走流式接口，实时展示「分析想法→搜索地点→规划路线→快好了」
- 流式失败时回退普通 POST，客户端轮播进度文案作为后备
- 规划阶段 UI 显示 planStatusMessage 替代静态文案

src/app/blindbox/[code]/page.tsx

@@ -51,6 +51,13 @@ interface RoomInfo {
 
 type Phase = "pool" | "shaking" | "reveal" | "time_select" | "planning" | "plan_reveal";
 
+const PLAN_STATUS_STEPS = [
+  "正在分析你们的想法...",
+  "正在搜索地点...",
+  "正在规划路线...",
+  "快好了...",
+];
+
 const IDEA_INSPIRATIONS = [
   "去城市最高楼看日落",
   "挑战一人做一道菜",
@@ -109,6 +116,7 @@ export default function BlindboxRoomPage() {
   const [planDays, setPlanDays] = useState<WeekendPlanData[]>([]);
   const [planAccepted, setPlanAccepted] = useState(false);
   const [generating, setGenerating] = useState(false);
+  const [planStatusMessage, setPlanStatusMessage] = useState("正在分析你们的想法...");
   const [showPlanShareCard, setShowPlanShareCard] = useState(false);
   const [activeContract, setActiveContract] = useState<{
     id: string;
@@ -335,30 +343,81 @@ export default function BlindboxRoomPage() {
     setGenerating(true);
     setPhase("planning");
     setError("");
+    setPlanStatusMessage(PLAN_STATUS_STEPS[0]);
+    const payload = {
+      roomId: room.id,
+      userId: profile.id,
+      availableTime: timeConfig,
+    };
+    const stepRef = { current: 0 };
+    const fallbackTimer = setInterval(() => {
+      stepRef.current = (stepRef.current + 1) % PLAN_STATUS_STEPS.length;
+      setPlanStatusMessage(PLAN_STATUS_STEPS[stepRef.current]);
+    }, 2800);
     try {
-      const res = await fetch("/api/blindbox/plan", {
+      const res = await fetch("/api/blindbox/plan/stream", {
         method: "POST",
         headers: { "Content-Type": "application/json" },
-        body: JSON.stringify({
-          roomId: room.id,
-          userId: profile.id,
-          availableTime: timeConfig,
-        }),
+        body: JSON.stringify(payload),
       });
       if (!res.ok) {
-        const data = await res.json();
+        const data = await res.json().catch(() => ({}));
         throw new Error(data.error || "生成失败");
       }
-      const data = await res.json();
-      setPlanId(data.id);
-      setPlanDays(data.days);
-      setPlanAccepted(false);
-      setPhase("plan_reveal");
-      fireConfetti();
+      const reader = res.body?.getReader();
+      const decoder = new TextDecoder();
+      if (!reader) throw new Error("无法读取响应");
+      let buffer = "";
+      while (true) {
+        const { done, value } = await reader.read();
+        if (done) break;
+        buffer += decoder.decode(value, { stream: true });
+        const blocks = buffer.split("\n\n");
+        buffer = blocks.pop() ?? "";
+        for (const block of blocks) {
+          let eventType = "";
+          let data = "";
+          for (const line of block.split("\n")) {
+            if (line.startsWith("event:")) eventType = line.slice(6).trim();
+            else if (line.startsWith("data:")) data = line.slice(5).trim();
+          }
+          if (eventType === "status") setPlanStatusMessage(data);
+          else if (eventType === "plan") {
+            const parsed = JSON.parse(data);
+            setPlanId(parsed.id);
+            setPlanDays(parsed.days);
+            setPlanAccepted(false);
+            setPhase("plan_reveal");
+            fireConfetti();
+          } else if (eventType === "error") {
+            setError(data || "生成计划失败");
+            setPhase("pool");
+          }
+        }
+      }
     } catch (e) {
-      setError(e instanceof Error ? e.message : "生成计划失败");
-      setPhase("pool");
+      try {
+        const res = await fetch("/api/blindbox/plan", {
+          method: "POST",
+          headers: { "Content-Type": "application/json" },
+          body: JSON.stringify(payload),
+        });
+        if (!res.ok) {
+          const data = await res.json().catch(() => ({}));
+          throw new Error(data.error || "生成失败");
+        }
+        const data = await res.json();
+        setPlanId(data.id);
+        setPlanDays(data.days);
+        setPlanAccepted(false);
+        setPhase("plan_reveal");
+        fireConfetti();
+      } catch (fallbackErr) {
+        setError(fallbackErr instanceof Error ? fallbackErr.message : "生成计划失败");
+        setPhase("pool");
+      }
     } finally {
+      clearInterval(fallbackTimer);
       setGenerating(false);
     }
   }, [generating, profile, room]);
@@ -961,7 +1020,7 @@ export default function BlindboxRoomPage() {
                   <Sparkles size={28} className="relative text-purple-400" />
                 </motion.div>
                 <p className="text-sm font-bold text-purple-300 animate-pulse">
-                  AI 正在规划你的周末...
+                  {planStatusMessage}
                 </p>
                 <p className="text-[11px] text-dim">搜索地点 · 优化路线 · 安排时间</p>
               </motion.div>