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-tauri/capabilities/default.json

@@ -11,7 +11,8 @@
     {
       "identifier": "http:default",
       "allow": [
-        { "url": "https://nostr.build/**" }
+        { "url": "https://nostr.build/**" },
+        { "url": "https://relay.vertexlab.io/**" }
       ]
     },
     "dialog:default",