feat: sprint 1 — auth + CRUD engagements

Ship the first feature end-to-end on the UI: users log in with JWT,
admins manage user accounts, and any authenticated user (per RBAC)
can create, list, view, edit, and delete engagements.

Backend (Flask + SQLAlchemy + SQLite, 63 pytest)
- User / Engagement models, Alembic 0001 initial schema
- argon2 password hashing, JWT bearer (60-min TTL), @login_required
  and @role_required decorators
- 13 API endpoints under /api/*, including last-admin protection on
  DELETE/PATCH user and JSON 404 on unknown /api/* paths
- `flask create-admin` CLI with duplicate / short-password handling

Frontend (React + Vite + Tailwind + TanStack Query, 20 vitest)
- Inter font bundled locally (no CDN), DESIGN.md tokens in Tailwind
- LoginPage / EngagementsList / EngagementForm / EngagementDetail /
  UsersAdmin pages with role-aware UI
- Layout, ProtectedRoute, StatusBadge, FormField, LoadingState,
  ErrorState, EmptyState, Toast + provider
- Axios client: Bearer interceptor, 401 → purge + /login + "Session
  expirée" toast, 403 → "Accès refusé" toast (declarative <Navigate>
  for already-authed users, Fragment-keyed admin user rows)

Deployment
- Single multistage Dockerfile (node:20-alpine → python:3.12-slim)
- docker/entrypoint.sh runs `flask db upgrade` before `flask run`
- Makefile: build/start/stop/restart/update/logs/create-admin/
  update-mitre/test-{backend,frontend,e2e}/clean
- .env.example documenting MIMIC_JWT_SECRET / MIMIC_DB_PATH / MIMIC_PORT
- SQLite at /data/mimic.sqlite on named volume mimic-data

Acceptance suite (Playwright, 36 tests, all 27 ACs)
- e2e/ scaffold with playwright.config + auth/api fixtures
- One spec per user story (us1-bootstrap through us6-deployment)
- Portable via MIMIC_CONTAINER_CMD / MIMIC_BASE_URL (docker or podman)

Docs
- README.md with quick-start and architecture overview
- CHANGELOG.md updated with Sprint 1 deliverables
- pyrightconfig.json so the Python LSP sees backend/.venv and
  resolves the `backend.app.*` absolute imports

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/ErrorState.tsx

@@ -0,0 +1,23 @@
+interface ErrorStateProps {
+  title?: string;
+  message: string;
+  onRetry?: () => void;
+}
+
+export function ErrorState({ title = 'Something went wrong', message, onRetry }: ErrorStateProps): JSX.Element {
+  return (
+    <div
+      role="alert"
+      data-testid="error-state"
+      className="card-product border border-bloom-deep/20 flex flex-col items-start gap-md"
+    >
+      <h2 className="text-[24px] font-medium text-bloom-deep">{title}</h2>
+      <p className="text-[16px] text-charcoal">{message}</p>
+      {onRetry ? (
+        <button type="button" className="btn-outline" onClick={onRetry}>
+          Retry
+        </button>
+      ) : null}
+    </div>
+  );
+}