feat: add is_chat field to board memory and task_id to approvals, update pagination and response models

backend/app/db/pagination.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from collections.abc import Awaitable, Callable, Sequence
+from typing import Any, TypeVar, cast
+
+from fastapi_pagination.ext.sqlalchemy import paginate as _paginate
+from sqlmodel.ext.asyncio.session import AsyncSession
+from sqlmodel.sql.expression import Select, SelectOfScalar
+
+from app.schemas.pagination import DefaultLimitOffsetPage
+
+T = TypeVar("T")
+
+Transformer = Callable[[Sequence[Any]], Sequence[Any] | Awaitable[Sequence[Any]]]
+
+
+async def paginate(
+    session: AsyncSession,
+    statement: Select[Any] | SelectOfScalar[Any],
+    *,
+    transformer: Transformer | None = None,
+) -> DefaultLimitOffsetPage[T]:
+    # fastapi-pagination is not fully typed (it returns Any), but response_model validation
+    # ensures runtime correctness. Centralize casts here to keep strict mypy clean.
+    return cast(
+        DefaultLimitOffsetPage[T],
+        await _paginate(session, statement, transformer=transformer),
+    )