feat: user relay management, blog naddr sync, and OG image update

Add UserRelay API and dashboard relays tab with NIP-65 import, store post
naddr for Nostr articles, and ship Prisma migrations for board tables,
user relays, and post metadata.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/app/blog/page.tsx

@@ -18,7 +18,7 @@ interface Post {
   authorPubkey?: string;
   publishedAt?: string;
   createdAt?: string;
-  categories?: { id: string; name: string; slug: string }[];
+  categories?: { category: { id: string; name: string; slug: string } }[];
   featured?: boolean;
 }
 
@@ -212,12 +212,12 @@ export default function BlogPage() {
                   >
                     {post.categories && post.categories.length > 0 && (
                       <div className="flex flex-wrap gap-2 mb-4">
-                        {post.categories.map((cat) => (
+                        {post.categories.map((pc) => (
                           <span
-                            key={cat.id}
+                            key={pc.category.id}
                             className="text-primary text-[10px] uppercase tracking-widest font-bold"
                           >
-                            {cat.name}
+                            {pc.category.name}
                           </span>
                         ))}
                       </div>