feat: add board group models and update related interfaces

backend/app/schemas/board_groups.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from datetime import datetime
+from uuid import UUID
+
+from sqlmodel import SQLModel
+
+
+class BoardGroupBase(SQLModel):
+    name: str
+    slug: str
+    description: str | None = None
+
+
+class BoardGroupCreate(BoardGroupBase):
+    pass
+
+
+class BoardGroupUpdate(SQLModel):
+    name: str | None = None
+    slug: str | None = None
+    description: str | None = None
+
+
+class BoardGroupRead(BoardGroupBase):
+    id: UUID
+    created_at: datetime
+    updated_at: datetime