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>

backend/app/api/auth.py

@@ -0,0 +1,46 @@
+"""Auth endpoints: login, logout, me."""
+from __future__ import annotations
+
+from flask import Blueprint, g, jsonify, request
+
+from backend.app.auth import encode_token, login_required, verify_password
+from backend.app.models import User
+from backend.app.serializers import serialize_user
+
+auth_bp = Blueprint("auth", __name__, url_prefix="/api/auth")
+
+
+@auth_bp.post("/login")
+def login():
+    data = request.get_json(silent=True) or {}
+    username = (data.get("username") or "").strip()
+    password = data.get("password") or ""
+
+    generic_error = (jsonify({"error": "Invalid credentials"}), 401)
+    if not username or not password:
+        return generic_error
+
+    user = User.query.filter_by(username=username).first()
+    if user is None or not verify_password(user.password_hash, password):
+        return generic_error
+
+    token = encode_token(user.id, user.role.value)
+    return jsonify(
+        {
+            "access_token": token,
+            "user": {"id": user.id, "username": user.username, "role": user.role.value},
+        }
+    ), 200
+
+
+@auth_bp.post("/logout")
+@login_required
+def logout():
+    # V1: stateless JWT — client discards the token. No server-side blacklist.
+    return jsonify({"status": "ok"}), 200
+
+
+@auth_bp.get("/me")
+@login_required
+def me():
+    return jsonify(serialize_user(g.current_user)), 200