fix(presence): broadcast presence_update to friends + DM members + space members

Six WS sites that previously broadcast presence_update to spaces only now use
collectProfileBroadcastTargetIds (the same recipient set as user_updated):
  - ws/handler.ts finalizeDisconnect (offline)
  - ws/handler.ts auth path (online)
  - ws/events.ts handlePresenceUpdate (manual idle/dnd/online)
  - ws/events.ts handleActivityUpdate (rich activity changes)
  - routes/users.ts showActivity-toggle clear
  - routes/users.ts status PATCH

Friends with no shared space + DM-only co-members now see each other's
online/offline transitions live, matching user_updated semantics. Federated
stub presence broadcasts (Task B3) use the same helper, so cross-instance
recipients are uniform.

Updates one assertion in social.federated.test.ts that asserted the old
snowflake-style stub username (now realname-based per A1).

packages/server/src/ws/handler.ts

@@ -21,6 +21,7 @@ import type {
   Activity,
 } from '@backspace/shared';
 import { sanitizeUser } from '../utils/sanitize.js';
+import { collectProfileBroadcastTargetIds } from '../utils/userDeletion.js';
 
 // ─── Heartbeat State ──────────────────────────────────────────────────────────
 const wsIsAlive: WeakMap<WebSocket, boolean> = new WeakMap();
@@ -296,16 +297,18 @@ class ConnectionManager {
     this.userStatuses.delete(userId);
     this.lastActivityUpdate.delete(userId);
 
-    // Broadcast offline to all spaces
-    const userSpaces = this.getUserSpaces(userId);
-    for (const spaceId of userSpaces) {
-      this.sendToSpace(spaceId, {
-        type: 'presence_update',
-        userId: userId,
-        status: 'offline',
-        activities: [] as Activity[],
-      });
-    }
+    // Broadcast offline to friends + DM co-members + space co-members.
+    // Mirrors collectProfileBroadcastTargetIds (the recipient set used by
+    // user_updated). Two locally-friended users with no shared space now see
+    // each other's offline transitions live, instead of being space-only.
+    const offlinePayload = {
+      type: 'presence_update' as const,
+      userId,
+      status: 'offline' as const,
+      activities: [] as Activity[],
+    };
+    const offlineTargets = collectProfileBroadcastTargetIds(userId);
+    for (const uid of offlineTargets) this.sendToUser(uid, offlinePayload);
 
     // S2S: project offline to all active peers (mirrors profile_update fanout).
     // Imported lazily to avoid circular import (federationPresence → db → ws/handler).
@@ -1669,15 +1672,10 @@ export async function registerWebSocket(app: FastifyInstance): Promise<void> {
             ...readyData,
           }));
 
-          // Broadcast presence update to all spaces
-          const userSpaces = connectionManager.getUserSpaces(userId);
-          for (const spaceId of userSpaces) {
-            connectionManager.sendToSpace(spaceId, {
-              type: 'presence_update',
-              userId,
-              status: 'online',
-            }, userId);
-          }
+          // Broadcast online to friends + DM co-members + space co-members.
+          const onlinePayload = { type: 'presence_update' as const, userId, status: 'online' as const };
+          const onlineTargets = collectProfileBroadcastTargetIds(userId);
+          for (const uid of onlineTargets) connectionManager.sendToUser(uid, onlinePayload);
 
           // S2S: project online to all active peers (mirrors profile_update fanout).
           const _uid = userId;