fix(admin): persist data directory and pass env vars

app/api/admin/media/route.ts

@@ -0,0 +1,38 @@
+import { mkdir, readdir, writeFile } from "fs/promises";
+import path from "path";
+import { NextResponse } from "next/server";
+import { requireAdminSession } from "@/lib/admin/auth";
+
+const uploadDir = path.join(process.cwd(), "public", "uploads", "images");
+const allowedTypes = new Set(["image/jpeg", "image/png", "image/webp", "application/pdf"]);
+
+async function ensureUploadDir() {
+  await mkdir(uploadDir, { recursive: true });
+}
+
+export async function GET() {
+  if (!await requireAdminSession()) return NextResponse.json({ message: "Nicht autorisiert." }, { status: 401 });
+  await ensureUploadDir();
+  const files = await readdir(uploadDir);
+  return NextResponse.json({
+    files: files.map((file) => ({ name: file, url: `/uploads/images/${file}` })),
+  });
+}
+
+export async function POST(request: Request) {
+  if (!await requireAdminSession()) return NextResponse.json({ message: "Nicht autorisiert." }, { status: 401 });
+  await ensureUploadDir();
+  const form = await request.formData();
+  const file = form.get("file");
+
+  if (!(file instanceof File) || !allowedTypes.has(file.type) || file.size > 5 * 1024 * 1024) {
+    return NextResponse.json({ message: "Bitte eine JPG-, PNG-, WebP- oder PDF-Datei bis 5 MB hochladen." }, { status: 400 });
+  }
+
+  const extension = path.extname(file.name).toLowerCase();
+  const safeName = `${Date.now()}-${file.name.toLowerCase().replace(/[^a-z0-9.-]/g, "-")}`;
+  const target = safeName.endsWith(extension) ? safeName : `${safeName}${extension}`;
+  await writeFile(path.join(uploadDir, target), Buffer.from(await file.arrayBuffer()));
+
+  return NextResponse.redirect(new URL("/admin/medien?uploaded=1", request.url));
+}