refactor: 提取 useToast hook + Toast 组件，消除 4 处重复的通知逻辑

将 state + setTimeout 自动消失逻辑封装为 useToast hook，
Toast UI 统一为组件支持 top/bottom 两种位置，净减约 12 行。

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

@@ -23,6 +23,8 @@ import {
 import confetti from "canvas-confetti";
 import { getCachedProfile, isRegistered } from "@/lib/userId";
 import ShareCardModal from "@/components/ShareCardModal";
+import Toast from "@/components/Toast";
+import { useToast } from "@/hooks/useToast";
 import { BlindboxRoomSkeleton } from "@/components/Skeleton";
 import type { UserProfile } from "@/types";
 
@@ -182,7 +184,7 @@ export default function BlindboxRoomPage() {
   const [error, setError] = useState("");
   const [showInvite, setShowInvite] = useState(false);
   const [showShareCard, setShowShareCard] = useState(false);
-  const [toast, setToast] = useState("");
+  const toast = useToast();
   const [confirmLeave, setConfirmLeave] = useState(false);
   const [leaving, setLeaving] = useState(false);
 
@@ -314,8 +316,7 @@ export default function BlindboxRoomPage() {
       }
       setMyIdeas((prev) => prev.map((i) => (i.id === ideaId ? { ...i, content: trimmed } : i)));
     } catch (e) {
-      setToast(e instanceof Error ? e.message : "编辑失败");
-      setTimeout(() => setToast(""), 2200);
+      toast.show(e instanceof Error ? e.message : "编辑失败");
     }
   }, [profile]);
 
@@ -334,8 +335,7 @@ export default function BlindboxRoomPage() {
       setMyIdeas((prev) => prev.filter((i) => i.id !== ideaId));
       setPoolCount((c) => Math.max(0, c - 1));
     } catch (e) {
-      setToast(e instanceof Error ? e.message : "删除失败");
-      setTimeout(() => setToast(""), 2200);
+      toast.show(e instanceof Error ? e.message : "删除失败");
     }
   }, [profile]);
 
@@ -395,8 +395,7 @@ export default function BlindboxRoomPage() {
     if (!room) return;
     try {
       await navigator.clipboard.writeText(room.code);
-      setToast("房间号已复制");
-      setTimeout(() => setToast(""), 2000);
+      toast.show("房间号已复制");
     } catch { /* ignore */ }
   };
 
@@ -441,8 +440,7 @@ export default function BlindboxRoomPage() {
       }
       router.replace("/blindbox");
     } catch (e) {
-      setToast(e instanceof Error ? e.message : "操作失败");
-      setTimeout(() => setToast(""), 2200);
+      toast.show(e instanceof Error ? e.message : "操作失败");
       setConfirmLeave(false);
     } finally {
       setLeaving(false);
@@ -817,10 +815,7 @@ export default function BlindboxRoomPage() {
             drawer: revealedIdea.drawnBy ?? undefined,
             roomName: room.name,
           }}
-          onToast={(msg) => {
-            setToast(msg);
-            setTimeout(() => setToast(""), 2200);
-          }}
+          onToast={toast.show}
         />
       )}
 
@@ -855,19 +850,7 @@ export default function BlindboxRoomPage() {
         </motion.div>
       )}
 
-      {/* Toast */}
-      <AnimatePresence>
-        {toast && (
-          <motion.div
-            className="fixed bottom-8 left-1/2 -translate-x-1/2 rounded-full bg-surface px-4 py-2 text-xs font-semibold text-secondary shadow-xl ring-1 ring-border"
-            initial={{ opacity: 0, y: 20 }}
-            animate={{ opacity: 1, y: 0 }}
-            exit={{ opacity: 0, y: 20 }}
-          >
-            {toast}
-          </motion.div>
-        )}
-      </AnimatePresence>
+      <Toast message={toast.message} position="bottom" />
 
       <div className="h-8 shrink-0" />
     </div>