fix: repair invite links, social features, messaging + Discord UI overhaul

Phase 1 - Feature Repair:
- Fix member kick/leave: add missing db.delete() call in servers.ts
- Stabilize invite codes: return existing code instead of regenerating
- Fix user search: use LIKE instead of exact match in social.ts
- Wire DM button on FriendsPage to create/navigate to DM channels
- Add cancel outgoing friend request (DELETE endpoint + frontend)
- Add accept/decline friend request actions with WS real-time events
- Fix replyToId persistence in message creation
- Hydrate reactions and replyTo in message queries
- Add joinByCode to API client and serverStore
- Add friend_request_received/accepted WebSocket events

Phase 2 - Discord UI Overhaul:
- Remove stray borders between layout columns
- Replace shadow-sm with shadow-header on content headers
- Replace all bg-gray-*/text-gray-* with Discord color tokens
- Ensure flat color contrast (#1E1F22, #2B2D31, #313338)

Testing:
- Set up vitest + @testing-library/react + jsdom
- Add 17 tests across InviteModal, JoinServer, FriendsPage (all passing)
- Fix vite resolve.extensions to prefer .tsx over stale .js files

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

@@ -8,6 +8,7 @@ interface VoiceUserProps {
 
 export function VoiceUser({ participant }: VoiceUserProps) {
   const videoRef = useRef<HTMLVideoElement>(null);
+  const audioRef = useRef<HTMLAudioElement>(null);
 
   useEffect(() => {
     const videoEl = videoRef.current;
@@ -22,7 +23,16 @@ export function VoiceUser({ participant }: VoiceUserProps) {
     }
   }, [participant.videoTrack, participant.screenTrack]);
 
+  useEffect(() => {
+    const audioEl = audioRef.current;
+    if (!audioEl || !participant.audioTrack) return;
+
+    const stream = new MediaStream([participant.audioTrack]);
+    audioEl.srcObject = stream;
+  }, [participant.audioTrack]);
+
   const hasVideo = participant.isCameraOn || participant.isScreenSharing;
+  const isLocal = participant.isLocal;
 
   return (
     <div
@@ -31,12 +41,15 @@ export function VoiceUser({ participant }: VoiceUserProps) {
       }`}
       style={{ aspectRatio: '16/9', minHeight: '200px' }}
     >
+      {/* Audio element for remote participants */}
+      {!isLocal && <audio ref={audioRef} autoPlay />}
+
       {hasVideo ? (
         <video
           ref={videoRef}
           autoPlay
           playsInline
-          muted={participant.userId === 'local'}
+          muted={isLocal}
           className="w-full h-full object-cover"
         />
       ) : (