M1: implement operational core

Demo auth, seed import/reset, dashboard, vehicle/booking list+detail, audit trail. Backend: 19 tests passing, ruff clean. Frontend: React Router shell, typed API client, responsive pages. Verified end-to-end via curl and browser.

backend/tests/test_seed.py

@@ -0,0 +1,46 @@
+from sqlalchemy import func, select
+
+from app.core.db import SessionLocal
+from app.models.booking import Booking
+from app.models.customer import Customer
+from app.models.data_quality import DataQualityIssue
+from app.models.outbox import OutboxEvent
+from app.models.user import User
+from app.models.vehicle import Vehicle
+
+
+def test_seed_counts_match_deterministic_dataset():
+    db = SessionLocal()
+    try:
+        assert db.scalar(select(func.count()).select_from(Vehicle)) == 50
+        assert db.scalar(select(func.count()).select_from(Customer)) == 180
+        assert db.scalar(select(func.count()).select_from(Booking)) == 246
+        assert db.scalar(select(func.count()).select_from(DataQualityIssue)) == 15
+        assert db.scalar(select(func.count()).select_from(OutboxEvent)) == 20
+        assert db.scalar(select(func.count()).select_from(User)) == 2
+    finally:
+        db.close()
+
+
+def test_seed_demo_scenarios_present():
+    db = SessionLocal()
+    try:
+        booking = db.scalar(select(Booking).where(Booking.public_ref == "BK-DEMO-RETURN"))
+        assert booking is not None
+        assert booking.status == "active"
+
+        duplicate_customer = db.scalar(select(Customer).where(Customer.public_ref == "CUS-0178"))
+        assert duplicate_customer is not None
+
+        duplicate_issue = db.scalar(
+            select(DataQualityIssue).where(DataQualityIssue.public_ref == "DQ-DEMO-DUPLICATE")
+        )
+        assert duplicate_issue is not None
+        assert duplicate_issue.rule_type == "possible_duplicate_customer"
+
+        failed_run = db.scalar(
+            select(OutboxEvent).where(OutboxEvent.delivery_status == "failed")
+        )
+        assert failed_run is not None
+    finally:
+        db.close()