Add mute/ignore user + anti-spam (roadmap #5, NIP-51)

- fetchMuteList / publishMuteList in nostr client (kind 10000)
- mute store: mutedPubkeys persisted to localStorage + synced to relay;
  mute/unmute publish kind 10000 best-effort; fetchMuteList merges relay
  list with local mutes on login
- fetchMuteList called after every login (nsec + pubkey)
- Feed: muted pubkeys filtered from both Global and Following tabs
- NoteCard: ⋯ context menu (appears on hover, hidden for own notes)
  with mute / unmute action; backdrop click closes menu
- ProfileView: mute / unmute button in the action row (next to follow)
- SettingsView: MuteSection lists muted accounts with name + avatar;
  hover to reveal unmute button; hidden when mute list is empty

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/profile/ProfileView.tsx

@@ -2,6 +2,7 @@ import { useEffect, useState } from "react";
 import { NDKEvent } from "@nostr-dev-kit/ndk";
 import { useUIStore } from "../../stores/ui";
 import { useUserStore } from "../../stores/user";
+import { useMuteStore } from "../../stores/mute";
 import { useProfile, invalidateProfileCache } from "../../hooks/useProfile";
 import { fetchUserNotes, publishProfile } from "../../lib/nostr";
 import { shortenPubkey } from "../../lib/utils";
@@ -116,6 +117,8 @@ export function ProfileView() {
   const [showZap, setShowZap] = useState(false);
 
   const isFollowing = follows.includes(pubkey);
+  const { mutedPubkeys, mute, unmute } = useMuteStore();
+  const isMuted = mutedPubkeys.includes(pubkey);
 
   const handleFollowToggle = async () => {
     setFollowPending(true);
@@ -185,6 +188,16 @@ export function ProfileView() {
             >
               {followPending ? "…" : isFollowing ? "unfollow" : "follow"}
             </button>
+            <button
+              onClick={() => isMuted ? unmute(pubkey) : mute(pubkey)}
+              className={`text-[11px] px-3 py-1 border transition-colors ${
+                isMuted
+                  ? "border-danger/40 text-danger hover:bg-danger/5"
+                  : "border-border text-text-dim hover:text-danger hover:border-danger/40"
+              }`}
+            >
+              {isMuted ? "unmute" : "mute"}
+            </button>
           </div>
         )}
       </header>