✨ Add ContestTaskPair type (#2627)

Author: KATO-Hiro

src/lib/types/contest_task_pair.ts

@@ -0,0 +1,5 @@
+import type { ContestTaskPair as ContestTaskPairOrigin } from '@prisma/client';
+
+export type ContestTaskPair = ContestTaskPairOrigin;
+
+export type ContestTaskPairs = ContestTaskPair[];