feat: real-time user profile updates and propagate avatarColor to all Avatar callsites

Broadcast user_updated events over WebSocket when profile fields change,
updating members, DM participants, friends, and cached messages in real time.
Widen useVoiceParticipantMeta to return the full user object and add a
standalone avatarColor prop to Avatar so all ~16 callsites now resolve
the user's chosen gradient color instead of falling back to hash-based colors.

packages/web/src/components/voice/StreamTile.tsx

@@ -20,7 +20,7 @@ export function StreamTile({ tile, large }: StreamTileProps) {
   const isLocal = participant.isLocal;
   const userId = participant.userId;
   const avatarUserId = participant.homeUserId ?? userId;
-  const { displayName, avatar } = useVoiceParticipantMeta(participant);
+  const { displayName, avatar, user } = useVoiceParticipantMeta(participant);
 
   const isWatching = watchingStreams.has(userId);
 
@@ -110,7 +110,7 @@ export function StreamTile({ tile, large }: StreamTileProps) {
       ) : (
         <div className="w-full h-full flex flex-col items-center justify-center gap-3 bg-surface-channel">
           <div className="relative">
-            <Avatar src={avatar} name={displayName} size={large ? 80 : 48} userId={avatarUserId} />
+            <Avatar src={avatar} name={displayName} size={large ? 80 : 48} userId={avatarUserId} user={user ?? undefined} />
           </div>
           <div className="text-center px-4">
             <p className="text-txt-primary text-sm font-semibold">