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/Dockerfile

@@ -1,13 +1,14 @@
 FROM python:3.12-slim
 ENV PYTHONDONTWRITEBYTECODE=1 PYTHONUNBUFFERED=1
 WORKDIR /app
-COPY requirements.lock ./
+COPY backend/requirements.lock ./
 RUN pip install --no-cache-dir -r requirements.lock
-COPY pyproject.toml ./
-COPY app ./app
-COPY alembic ./alembic
-COPY alembic.ini ./
-COPY tests ./tests
+COPY backend/pyproject.toml ./
+COPY backend/app ./app
+COPY backend/alembic ./alembic
+COPY backend/alembic.ini ./
+COPY backend/tests ./tests
+COPY seed ./seed
 RUN pip install --no-cache-dir --no-deps -e .
 EXPOSE 8000
 CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]