feat: add path traversal protection middleware

Implement security middleware to prevent directory traversal attacks by detecting and blocking requests containing ".." in decoded URL paths

middleware.ts

@@ -0,0 +1,17 @@
+import { NextRequest, NextResponse } from "next/server";
+
+export function middleware(request: NextRequest) {
+  const { pathname } = request.nextUrl;
+
+  const decodedPath = decodeURIComponent(pathname);
+
+  if (decodedPath.includes("..")) {
+    return new NextResponse("Bad Request", { status: 400 });
+  }
+
+  return NextResponse.next();
+}
+
+export const config = {
+  matcher: "/:path*",
+};