refactor: rename proxy.ts to middleware.ts and update function name to middleware

shop/middleware.ts

@@ -1,7 +1,7 @@
 import { updateSession } from "@/lib/supabase/proxy";
 import { type NextRequest } from "next/server";
 
-export async function proxy(request: NextRequest) {
+export async function middleware(request: NextRequest) {
   return await updateSession(request);
 }