feat(gateway): service-accounts management endpoints (Stage 1 PR4)

Owner/admin self-service CRUD for service accounts: POST create,
GET list, PATCH status; workspace-scoped with 404 existence hiding
for cross-workspace targets. Gated by require_workspace_admin.

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

backend/tests/test_service_accounts_router.py

@@ -0,0 +1,123 @@
+"""service-accounts router tests (Stage 1 PR4)."""
+
+from __future__ import annotations
+
+import pytest
+from starlette.testclient import TestClient
+
+pytestmark = pytest.mark.anyio
+
+
+@pytest.fixture
+def anyio_backend() -> str:
+    return "asyncio"
+
+
+async def _init_db(tmp_path):
+    from deerflow.persistence.engine import get_session_factory, init_engine
+    from deerflow.persistence.user.model import UserRow
+    from deerflow.persistence.workspace.model import WorkspaceRow
+
+    url = f"sqlite+aiosqlite:///{tmp_path / 'test.db'}"
+    await init_engine("sqlite", url=url, sqlite_dir=str(tmp_path))
+    sf = get_session_factory()
+    async with sf() as session:
+        session.add(UserRow(id="u-alice", email="alice@example.com"))
+        await session.commit()
+    async with sf() as session:
+        session.add(WorkspaceRow(id="w-1", name="WS", slug="ws", owner_id="u-alice"))
+        await session.commit()
+
+
+async def _cleanup():
+    from deerflow.persistence.engine import close_engine
+
+    await close_engine()
+
+
+def _make_app(*, role="owner", user_id="u-alice", workspace_id="w-1"):
+    """App that stamps a fixed principal + workspace, then mounts the router.
+
+    A tiny inline middleware substitutes for AuthMiddleware so the test
+    controls role/user/workspace directly.
+    """
+    from fastapi import FastAPI, Request
+    from starlette.middleware.base import BaseHTTPMiddleware
+
+    from app.gateway.authz import _ALL_PERMISSIONS, AuthContext
+    from app.gateway.routers import service_accounts
+    from deerflow.runtime.user_context import reset_current_user, set_current_user
+    from deerflow.runtime.workspace_context import reset_current_workspace, set_current_workspace
+
+    class _Stamp(BaseHTTPMiddleware):
+        async def dispatch(self, request: Request, call_next):
+            user = type("U", (), {"id": user_id, "is_service_account": False})()
+            ws = type("W", (), {"id": workspace_id, "role": role})()
+            request.state.user = user
+            request.state.auth = AuthContext(user=user, permissions=_ALL_PERMISSIONS)
+            ut = set_current_user(user)
+            wt = set_current_workspace(ws)
+            try:
+                return await call_next(request)
+            finally:
+                reset_current_workspace(wt)
+                reset_current_user(ut)
+
+    app = FastAPI()
+    app.add_middleware(_Stamp)
+    app.include_router(service_accounts.router)
+    return app
+
+
+async def test_owner_creates_and_lists_sa(tmp_path):
+    await _init_db(tmp_path)
+    try:
+        client = TestClient(_make_app(role="owner"))
+        r = client.post("/api/v1/service-accounts", json={"name": "ci-bot"})
+        assert r.status_code == 201, r.text
+        sa = r.json()
+        assert sa["name"] == "ci-bot"
+        assert sa["workspace_id"] == "w-1"
+        assert sa["created_by"] == "u-alice"
+
+        lst = client.get("/api/v1/service-accounts")
+        assert lst.status_code == 200
+        assert [s["id"] for s in lst.json()] == [sa["id"]]
+    finally:
+        await _cleanup()
+
+
+async def test_member_cannot_create_sa(tmp_path):
+    await _init_db(tmp_path)
+    try:
+        client = TestClient(_make_app(role="member"))
+        r = client.post("/api/v1/service-accounts", json={"name": "x"})
+        assert r.status_code == 403
+    finally:
+        await _cleanup()
+
+
+async def test_patch_status_suspend(tmp_path):
+    await _init_db(tmp_path)
+    try:
+        client = TestClient(_make_app(role="admin"))
+        sa = client.post("/api/v1/service-accounts", json={"name": "bot"}).json()
+        r = client.patch(f"/api/v1/service-accounts/{sa['id']}", json={"status": "suspended"})
+        assert r.status_code == 200
+        assert r.json()["status"] == "suspended"
+    finally:
+        await _cleanup()
+
+
+async def test_patch_other_workspace_sa_404(tmp_path):
+    await _init_db(tmp_path)
+    try:
+        # SA created in w-1
+        owner_client = TestClient(_make_app(role="owner", workspace_id="w-1"))
+        sa = owner_client.post("/api/v1/service-accounts", json={"name": "bot"}).json()
+        # Caller in a different workspace tries to patch it → 404
+        other_client = TestClient(_make_app(role="owner", workspace_id="w-2"))
+        r = other_client.patch(f"/api/v1/service-accounts/{sa['id']}", json={"status": "suspended"})
+        assert r.status_code == 404
+    finally:
+        await _cleanup()