feat: implement meal planning feature with CRUD operations and UI integration

frontend/app/api/meal-plan-proxy/shopping/route.ts

@@ -0,0 +1,17 @@
+import { NextRequest, NextResponse } from 'next/server';
+
+const API_BASE = process.env.NEXT_PUBLIC_API_URL_INTERNAL || 'http://recipe-api:8080';
+
+export async function GET(request: NextRequest) {
+  const { searchParams } = request.nextUrl;
+  const from = searchParams.get('from');
+  const to = searchParams.get('to');
+  const res = await fetch(`${API_BASE}/api/meal-plan/shopping-list?from=${from}&to=${to}`, {
+    cache: 'no-store',
+  });
+  const text = await res.text();
+  return new NextResponse(text, {
+    status: res.status,
+    headers: { 'Content-Type': 'application/json' },
+  });
+}