refactor: update module docstrings for clarity and consistency

backend/app/schemas/board_groups.py

@@ -1,28 +1,36 @@
+"""Schemas for board-group create/update/read API operations."""
+
 from __future__ import annotations
 
-from datetime import datetime
-from uuid import UUID
+from datetime import datetime  # noqa: TCH003
+from uuid import UUID  # noqa: TCH003
 
 from sqlmodel import SQLModel
 
 
 class BoardGroupBase(SQLModel):
+    """Shared board-group fields for create/read operations."""
+
     name: str
     slug: str
     description: str | None = None
 
 
 class BoardGroupCreate(BoardGroupBase):
-    pass
+    """Payload for creating a board group."""
 
 
 class BoardGroupUpdate(SQLModel):
+    """Payload for partial board-group updates."""
+
     name: str | None = None
     slug: str | None = None
     description: str | None = None
 
 
 class BoardGroupRead(BoardGroupBase):
+    """Board-group payload returned from read endpoints."""
+
     id: UUID
     organization_id: UUID
     created_at: datetime