Add Web of Trust reputation on profiles via Vertex DVM

Query Vertex Verify Reputation API (kind 5312) for each profile and
display "Followed by people you trust" with clickable top-follower
avatars. Includes in-memory cache, request dedup, and graceful
fallback when logged out or API unreachable.

src/hooks/useReputation.ts

@@ -0,0 +1,44 @@
+import { useEffect, useState } from "react";
+import { verifyReputation } from "../lib/nostr";
+import type { ReputationResult } from "../lib/nostr";
+import { useUserStore } from "../stores/user";
+
+const cache = new Map<string, ReputationResult | null>();
+const pending = new Map<string, Promise<ReputationResult | null>>();
+
+export function useReputation(pubkey: string): { data: ReputationResult | null; loading: boolean } {
+  const [data, setData] = useState<ReputationResult | null>(() => cache.get(pubkey) ?? null);
+  const [loading, setLoading] = useState(!cache.has(pubkey));
+  const loggedIn = useUserStore((s) => s.loggedIn);
+
+  useEffect(() => {
+    if (!loggedIn) {
+      setLoading(false);
+      return;
+    }
+
+    if (cache.has(pubkey)) {
+      setData(cache.get(pubkey)!);
+      setLoading(false);
+      return;
+    }
+
+    // Deduplicate concurrent requests
+    if (!pending.has(pubkey)) {
+      const request = verifyReputation(pubkey).then((result) => {
+        cache.set(pubkey, result);
+        pending.delete(pubkey);
+        return result;
+      });
+      pending.set(pubkey, request);
+    }
+
+    setLoading(true);
+    pending.get(pubkey)!.then((result) => {
+      setData(result);
+      setLoading(false);
+    });
+  }, [pubkey, loggedIn]);
+
+  return { data, loading };
+}