M9: create validated internal bookings

backend/tests/test_bookings.py

@@ -20,6 +20,28 @@ def test_list_bookings_supports_bounded_search_pages(ops_client):
     assert len(body["items"]) == 25
 
 
+def test_create_booking_rejects_overlap_and_audits_valid_booking(ops_client):
+    conflict = ops_client.post(
+        "/api/v1/bookings",
+        json={
+            "customer_ref": "CUS-0001", "vehicle_ref": "MO-024",
+            "starts_at": "2026-08-10T10:00:00Z", "ends_at": "2026-08-10T12:00:00Z",
+        },
+    )
+    assert conflict.status_code == 409
+    created = ops_client.post(
+        "/api/v1/bookings",
+        json={
+            "customer_ref": "CUS-0001", "vehicle_ref": "MO-001",
+            "starts_at": "2026-09-01T10:00:00Z", "ends_at": "2026-09-02T12:00:00Z",
+        },
+    )
+    assert created.status_code == 201
+    body = created.json()
+    assert body["status"] == "reserved"
+    assert body["vehicle_ref"] == "MO-001"
+
+
 def test_get_booking_detail(ops_client):
     response = ops_client.get("/api/v1/bookings/BK-DEMO-RETURN")
     assert response.status_code == 200