fix: keep tierlist saves consistent

app/api/tl/[ver]/sync/route.ts

@@ -0,0 +1,30 @@
+import { eq, sql } from "drizzle-orm";
+import { NextResponse } from "next/server";
+import { db } from "@/lib/db";
+import { tierlistStates, tierlistVersions } from "@/lib/db/schema";
+import type { TierlistSyncData } from "@/lib/tierlist-sync";
+
+export async function GET(
+  _req: Request,
+  { params }: { params: Promise<{ ver: string }> },
+) {
+  const { ver } = await params;
+  const data = await db.transaction(async (tx): Promise<TierlistSyncData> => {
+    await tx.execute(sql`SET TRANSACTION ISOLATION LEVEL REPEATABLE READ`);
+    const states = await tx
+      .select()
+      .from(tierlistStates)
+      .where(eq(tierlistStates.list, ver));
+    const [version] = await tx
+      .select({ placements: tierlistVersions.placements })
+      .from(tierlistVersions)
+      .where(eq(tierlistVersions.id, ver))
+      .limit(1);
+
+    return { states, placements: version?.placements ?? {} };
+  });
+
+  return NextResponse.json(data, {
+    headers: { "Cache-Control": "no-store, max-age=0" },
+  });
+}