feat(desktop): apply friend nicknames in header / bubble / mentions / call tile

apps/desktop/src/components/CallParticipantTile.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useRef } from 'react';
 
+import { useNickname } from '../lib/friendNicknames';
 import {
   CrownIcon,
   HeadphonesOffIcon,
@@ -89,6 +90,7 @@ export interface ParticipantTileProps {
 
 export function CallParticipantTile(props: ParticipantTileProps) {
   const {
+    userId,
     displayName,
     me,
     muted,
@@ -107,6 +109,13 @@ export function CallParticipantTile(props: ParticipantTileProps) {
     onContextMenu,
   } = props;
 
+  // Apply the per-viewer nickname override once at the top — each tile is
+  // already per-participant, so a single hook call is fine. The resolved
+  // name is forwarded into the avatar sub-components below so their initial
+  // letter respects the nickname too.
+  const resolvedName = useNickname(userId, displayName);
+  const tileProps = { ...props, displayName: resolvedName };
+
   const small = size === 'small';
   // Discord-style: full tile border switches to emerald the whole time the
   // user is speaking. Same treatment for audio + video tiles so the visual
@@ -132,9 +141,9 @@ export function CallParticipantTile(props: ParticipantTileProps) {
       }
     >
       {video ? (
-        <VideoStub {...props} small={small} fit={focused ? 'contain' : 'cover'} />
+        <VideoStub {...tileProps} small={small} fit={focused ? 'contain' : 'cover'} />
       ) : (
-        <AudioContent {...props} small={small} />
+        <AudioContent {...tileProps} small={small} />
       )}
 
       {speaking && (
@@ -187,7 +196,7 @@ export function CallParticipantTile(props: ParticipantTileProps) {
             />
           )}
           <span className="truncate">
-            {displayName}
+            {resolvedName}
             {me ? ' (du)' : ''}
           </span>
           {e2ee && (