feat: resolve live Nostr references in blog posts and add embeds

Support naddr/nevent/note slugs for unindexed posts, cache naddr lookups,
render Nostr embeds in markdown, and add a consistency check for events mirrors.

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

frontend/app/blog/[slug]/remarkNostr.ts

@@ -0,0 +1,64 @@
+import { nip19 } from "nostr-tools";
+
+// Matches NIP-27 `nostr:` references (and bare bech32 entities) embedded in
+// article text: npub/nprofile (mentions) and note/nevent/naddr (notes).
+const NOSTR_RE =
+  /(?:nostr:)?((?:npub|nprofile|note|nevent|naddr)1[023456789acdefghjklmnpqrstuvwxyz]+)/gi;
+
+function isValidEntity(bech32: string): boolean {
+  try {
+    const { type } = nip19.decode(bech32);
+    return ["npub", "nprofile", "note", "nevent", "naddr"].includes(type);
+  } catch {
+    return false;
+  }
+}
+
+// Splits a plain-text value into text + `link` nodes, where each link's url is
+// `nostr:<bech32>`. The markdown `a` renderer detects that scheme and swaps in
+// the live profile/note component.
+function splitText(value: string): any[] {
+  const out: any[] = [];
+  let last = 0;
+  NOSTR_RE.lastIndex = 0;
+  let m: RegExpExecArray | null;
+  while ((m = NOSTR_RE.exec(value)) !== null) {
+    const bech32 = m[1];
+    if (!isValidEntity(bech32)) continue;
+    if (m.index > last) {
+      out.push({ type: "text", value: value.slice(last, m.index) });
+    }
+    out.push({
+      type: "link",
+      url: `nostr:${bech32}`,
+      children: [{ type: "text", value: m[0] }],
+    });
+    last = m.index + m[0].length;
+  }
+  if (out.length === 0) return [{ type: "text", value }];
+  if (last < value.length) out.push({ type: "text", value: value.slice(last) });
+  return out;
+}
+
+// Remark plugin: walk the mdast tree and replace `nostr:` tokens inside text
+// nodes. Skips code and existing links so identifiers there are left untouched.
+export function remarkNostr() {
+  return (tree: any) => {
+    const walk = (node: any) => {
+      if (!node || !Array.isArray(node.children)) return;
+      const next: any[] = [];
+      for (const child of node.children) {
+        if (child.type === "text") {
+          next.push(...splitText(child.value));
+          continue;
+        }
+        if (child.type !== "link" && child.type !== "inlineCode" && child.type !== "code") {
+          walk(child);
+        }
+        next.push(child);
+      }
+      node.children = next;
+    };
+    walk(tree);
+  };
+}