fix：房间号更新改为pinia

src/store.js

@@ -79,6 +79,7 @@ export default defineStore("store", {
     game: {
       roomID: "",
       inBattle: false,
+      roomNumber: "", // 当前房间号，供 Header 展示房号胶囊
     },
   }),
 
@@ -135,6 +136,10 @@ export default defineStore("store", {
       this.game.roomID = roomID;
       this.game.inBattle = inBattle;
     },
+    /** 更新当前房间号，供 Header 组件展示房号胶囊 */
+    updateRoomNumber(number) {
+      this.game.roomNumber = number;
+    },
   },
 
   // 开启数据持久化