fix: await params in Next.js 16 routes and pages for TypeScript compatibility

src/app/api/tournaments/[id]/participants/route.ts

@@ -4,10 +4,11 @@ import { canManageTournament } from "@/lib/permissions";
 
 export async function POST(
   request: Request,
-  { params }: { params: { id: string } }
+  { params }: { params: Promise<{ id: string }> }
 ) {
   try {
-    const tournamentId = parseInt(params.id, 10);
+    const { id } = await params
+    const tournamentId = parseInt(id, 10);
     
     if (isNaN(tournamentId)) {
       return NextResponse.json(