fix: unify panic room code format and validate room join id

src/lib/validation.ts

@@ -48,3 +48,16 @@ export function requireString(value: unknown, fieldName: string): string {
   }
   return value;
 }
+
+const PANIC_ROOM_ID_REGEX = /^[A-Z0-9]{6}$/;
+
+export function validatePanicRoomId(raw: unknown): string {
+  if (!raw || typeof raw !== "string") {
+    throw new ApiError("roomId 不能为空");
+  }
+  const roomId = raw.trim().toUpperCase();
+  if (!PANIC_ROOM_ID_REGEX.test(roomId)) {
+    throw new ApiError("房间号格式无效，应为 6 位字母数字", 400);
+  }
+  return roomId;
+}