style(Nip): add icon, dotted underline, muted text for NIP links

src/components/nostr/RichText/Nip.tsx

@@ -1,3 +1,4 @@
+import { FileText } from "lucide-react";
 import type { NipNode } from "@/lib/nip-transformer";
 import { useGrimoire } from "@/core/state";
 import { getNIPInfo } from "@/lib/nip-icons";
@@ -25,10 +26,11 @@ export function Nip({ node }: NipNodeProps) {
   return (
     <button
       onClick={openNIP}
-      className="text-primary hover:underline"
+      className="inline-flex items-center gap-0.5 text-muted-foreground underline decoration-dotted hover:text-foreground cursor-crosshair"
       title={nipInfo?.description ?? `View NIP-${number} specification`}
     >
-      {raw}
+      <FileText className="size-3" />
+      <span>{raw}</span>
     </button>
   );
 }