fix(channel): enforce read-only for members and polish chat info

- block send/forward in channels for member role on backend
- expose my_role in chat payload for client-side permissions
- hide message composer for channel members and show read-only notice
- hide members management sections for private/saved chats in info panel
- return enriched chat detail via serialize_chat_for_user

app/chats/router.py

@@ -96,13 +96,12 @@ async def get_chat(
     current_user: User = Depends(get_current_user),
 ) -> ChatDetailRead:
     chat, members = await get_chat_for_user(db, chat_id=chat_id, user_id=current_user.id)
-    return ChatDetailRead(
-        id=chat.id,
-        type=chat.type,
-        title=chat.title,
-        pinned_message_id=chat.pinned_message_id,
-        created_at=chat.created_at,
-        members=members,
+    base = await serialize_chat_for_user(db, user_id=current_user.id, chat=chat)
+    return ChatDetailRead.model_validate(
+        {
+            **base.model_dump(),
+            "members": members,
+        }
     )
 
 

app/chats/schemas.py

@@ -26,6 +26,7 @@ class ChatRead(BaseModel):
     counterpart_username: str | None = None
     counterpart_is_online: bool | None = None
     counterpart_last_seen_at: datetime | None = None
+    my_role: ChatMemberRole | None = None
     created_at: datetime
 
 

app/chats/service.py

@@ -18,6 +18,10 @@ from app.users.repository import get_user_by_id
 
 async def serialize_chat_for_user(db: AsyncSession, *, user_id: int, chat: Chat) -> ChatRead:
     display_title = chat.title
+    my_role = None
+    membership = await repository.get_chat_member(db, chat_id=chat.id, user_id=user_id)
+    if membership:
+        my_role = membership.role
     members_count: int | None = None
     online_count: int | None = None
     subscribers_count: int | None = None
@@ -70,6 +74,7 @@ async def serialize_chat_for_user(db: AsyncSession, *, user_id: int, chat: Chat)
             "counterpart_username": counterpart_username,
             "counterpart_is_online": counterpart_is_online,
             "counterpart_last_seen_at": counterpart_last_seen_at,
+            "my_role": my_role,
             "created_at": chat.created_at,
         }
     )