fix: stabilize maintenance flow run/resume and procedural scrolling

backend/tests/test_maintenance_schedules.py

@@ -98,6 +98,23 @@ async def test_get_schedule_not_found(client: AsyncClient, auth_headers: dict):
     assert resp.status_code == 404
 
 
+@pytest.mark.asyncio
+async def test_cannot_create_schedule_for_non_maintenance_tree(
+    client: AsyncClient, auth_headers: dict, test_tree: dict
+):
+    """Schedules are restricted to maintenance flows."""
+    resp = await client.post(
+        "/api/v1/maintenance-schedules",
+        json={
+            "tree_id": test_tree["id"],
+            "cron_expression": "0 0 1 * *",
+            "timezone": "UTC",
+        },
+        headers=auth_headers,
+    )
+    assert resp.status_code == 400
+
+
 @pytest.mark.asyncio
 async def test_cannot_schedule_other_teams_tree(client: AsyncClient, auth_headers: dict, test_db):
     """User cannot create a schedule for a tree belonging to another team."""