feat(persistence): ExternalUserRepository scaffold (Stage 1 PR1)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/packages/harness/deerflow/persistence/external_user/sql.py

@@ -0,0 +1,98 @@
+"""SQLAlchemy-backed external user repository (Stage 1 PR1).
+
+Built but NOT yet wired to any auth path — the X-External-User-Id
+passthrough that calls ``upsert`` lands in a later track-2 PR. ``upsert``
+is idempotent on (service_account_id, external_id).
+"""
+
+from __future__ import annotations
+
+import uuid
+from datetime import UTC, datetime
+from typing import Any
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
+
+from deerflow.persistence.external_user.model import ExternalUserRow
+
+
+class ExternalUserRepository:
+    def __init__(self, session_factory: async_sessionmaker[AsyncSession]) -> None:
+        self._sf = session_factory
+
+    @staticmethod
+    def _row_to_dict(row: ExternalUserRow) -> dict[str, Any]:
+        return {
+            "id": row.id,
+            "workspace_id": row.workspace_id,
+            "service_account_id": row.service_account_id,
+            "external_id": row.external_id,
+            "display_name": row.display_name,
+            "metadata": dict(row.metadata_json or {}),
+            "created_at": row.created_at.isoformat() if row.created_at else None,
+            "last_seen_at": row.last_seen_at.isoformat() if row.last_seen_at else None,
+        }
+
+    async def get(self, external_user_id: str) -> dict[str, Any] | None:
+        async with self._sf() as session:
+            row = await session.get(ExternalUserRow, external_user_id)
+            return self._row_to_dict(row) if row else None
+
+    async def get_by_external_id(self, *, service_account_id: str, external_id: str) -> dict[str, Any] | None:
+        async with self._sf() as session:
+            result = await session.execute(
+                select(ExternalUserRow).where(
+                    ExternalUserRow.service_account_id == service_account_id,
+                    ExternalUserRow.external_id == external_id,
+                )
+            )
+            row = result.scalar_one_or_none()
+            return self._row_to_dict(row) if row else None
+
+    async def list_by_workspace(self, workspace_id: str) -> list[dict[str, Any]]:
+        async with self._sf() as session:
+            result = await session.execute(select(ExternalUserRow).where(ExternalUserRow.workspace_id == workspace_id).order_by(ExternalUserRow.created_at.desc()))
+            return [self._row_to_dict(r) for r in result.scalars()]
+
+    async def upsert(
+        self,
+        *,
+        workspace_id: str,
+        service_account_id: str,
+        external_id: str,
+        display_name: str | None = None,
+        metadata: dict[str, Any] | None = None,
+    ) -> dict[str, Any]:
+        """Insert a new external user or refresh ``last_seen_at`` on an
+        existing (service_account_id, external_id) row."""
+        now = datetime.now(UTC)
+        async with self._sf() as session:
+            result = await session.execute(
+                select(ExternalUserRow).where(
+                    ExternalUserRow.service_account_id == service_account_id,
+                    ExternalUserRow.external_id == external_id,
+                )
+            )
+            row = result.scalar_one_or_none()
+            if row is None:
+                row = ExternalUserRow(
+                    id=str(uuid.uuid4()),
+                    workspace_id=workspace_id,
+                    service_account_id=service_account_id,
+                    external_id=external_id,
+                    display_name=display_name,
+                    metadata_json=metadata or {},
+                    created_at=now,
+                    last_seen_at=now,
+                )
+                session.add(row)
+            else:
+                row.last_seen_at = now
+                if display_name is not None:
+                    row.display_name = display_name
+                if metadata is not None:
+                    row.metadata_json = metadata
+            await session.commit()
+            await session.refresh(row)
+            return self._row_to_dict(row)