fix: filter out system inboxes (*, user) from team member list

The broadcast inbox file (inboxes/*.json) was being parsed by
listInboxNames() as a member named "*", which appeared in the UI
as a phantom team member. Since "*" fails the MEMBER_NAME_PATTERN
validation, it could not be removed through the UI.

Filter system inbox names (*, user) from listInboxNames() so they
are not treated as real team members.

src/main/services/team/TeamInboxReader.ts

@@ -42,9 +42,14 @@ export class TeamInboxReader {
       throw error;
     }
 
+    // Exclude broadcast inbox (*.json) and user inbox (user.json) — these are
+    // system inboxes, not real team members. Without this filter, '*' appears
+    // as a phantom member in the UI that can't be removed.
+    const SYSTEM_INBOX_NAMES = new Set(['*', 'user']);
     return entries
       .filter((name) => name.endsWith('.json') && !name.startsWith('.'))
-      .map((name) => name.replace(/\.json$/, ''));
+      .map((name) => name.replace(/\.json$/, ''))
+      .filter((name) => !SYSTEM_INBOX_NAMES.has(name));
   }
 
   async getMessagesFor(teamName: string, member: string): Promise<InboxMessage[]> {