feat(moderation): add chat bans list endpoint with admin access checks

docs/api-reference.md

@@ -811,6 +811,22 @@ Auth required (`owner/admin` in group/channel).
 Response: `204`  
 Behavior: bans user from chat and removes membership if present.
 
+### GET `/api/v1/chats/{chat_id}/bans`
+
+Auth required (`owner/admin` in group/channel).  
+Response: `200` + `ChatBanRead[]`
+
+Example item:
+
+```json
+{
+  "chat_id": 42,
+  "user_id": 101,
+  "banned_by_user_id": 5,
+  "created_at": "2026-03-10T00:00:00Z"
+}
+```
+
 ### DELETE `/api/v1/chats/{chat_id}/bans/{user_id}`
 
 Auth required (`owner/admin` in group/channel).