feat: implement archiving functionality for counters and update related logic

app/api/counters/[id]/unarchive/route.ts

@@ -0,0 +1,14 @@
+import { NextResponse } from 'next/server';
+import db from '@/lib/db';
+
+export const dynamic = 'force-dynamic';
+
+type Params = { params: Promise<{ id: string }> };
+
+export async function POST(_req: Request, { params }: Params) {
+  const { id } = await params;
+  const existing = db.prepare('SELECT * FROM counters WHERE id = ?').get(Number(id));
+  if (!existing) return NextResponse.json({ error: 'Not found' }, { status: 404 });
+  const updated = db.prepare('UPDATE counters SET archived_at = NULL WHERE id = ? RETURNING *').get(Number(id));
+  return NextResponse.json(updated);
+}