feat(groups): include member profile fields in chat members API

docs/api-reference.md

@@ -771,7 +771,7 @@ Response: `200` + `ChatRead`
 ### GET `/api/v1/chats/{chat_id}/members`
 
 Auth required.  
-Response: `200` + `ChatMemberRead[]`
+Response: `200` + `ChatMemberRead[]` (includes `username`, `name`, `avatar_url` for each member)
 
 ### POST `/api/v1/chats/{chat_id}/members`
 

docs/core-checklist-status.md

@@ -29,7 +29,7 @@ Legend:
 20. GIF - `PARTIAL` (web GIF picker with Tenor search + preset fallback + favorites)
 21. Message History/Search - `DONE` (history/pagination/chat+global search)
 22. Text Formatting - `PARTIAL` (bold/italic/underline/spoiler/mono/links + strikethrough + quote/code block; toolbar still evolving)
-23. Groups - `PARTIAL` (create/add/remove/invite link; join-by-invite and invite permissions covered by integration tests; advanced moderation partial)
+23. Groups - `PARTIAL` (create/add/remove/invite link; join-by-invite and invite permissions covered by integration tests; members API now returns profile fields (`username/name/avatar_url`) for richer moderation UI; advanced moderation still partial)
 24. Roles - `DONE` (owner/admin/member)
 25. Admin Rights - `PARTIAL` (delete/pin/edit info + explicit ban APIs for groups/channels including ban list endpoint; integration tests cover channel member read-only, channel admin full-delete, channel message delete-for-all permissions, group profile edit permissions, owner-only role management rules, and admin-visible/member-forbidden ban-list access; remaining UX moderation tools limited)
 26. Channels - `PARTIAL` (create/post/edit/delete/subscribe/unsubscribe; UX edge-cases still polishing)