feat: media library with image picker for article forms, browse/upload from folder

src/app/admin/media/page.tsx

@@ -0,0 +1,17 @@
+import Link from "next/link";
+import { AdminMediaGrid } from "@/components/admin/media-grid";
+
+export default function AdminMediaPage() {
+  return (
+    <main>
+      <div style={{ display: "flex", alignItems: "center", justifyContent: "space-between" }}>
+        <h1>Media Library</h1>
+        <Link href="/admin/articles" className="muted" style={{ fontSize: "0.88rem" }}>← Articles</Link>
+      </div>
+      <p className="muted" style={{ marginTop: "-0.4rem" }}>
+        Upload and manage images for articles and other content.
+      </p>
+      <AdminMediaGrid />
+    </main>
+  );
+}