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

app/chats/schemas.py

@@ -111,3 +111,10 @@ class ChatInviteLinkRead(BaseModel):
 
 class ChatJoinByInviteRequest(BaseModel):
     token: str = Field(min_length=8, max_length=64)
+
+
+class ChatBanRead(BaseModel):
+    chat_id: int
+    user_id: int
+    banned_by_user_id: int
+    created_at: datetime