feat: initial scaffold — MVP catalogue de données d'API

- Backend NestJS : CRUD api_entries + categories, upload YAML multi-fichiers,
  génération docs AsyncAPI (@asyncapi/cli@6.0.0) et OpenAPI (redocly)
- Fix: route wildcard GET /api/apis/:id/*path pour servir les assets statiques
  (CSS/JS) générés par AsyncAPI HTML template (contournement bug path-to-regexp v8)
- Frontend Angular 19 : pages catalog, browse, api-detail, doc-viewer, upload (DSFR)
- Seeder de données de démo (idempotent)
- Docker Compose dev + Dockerfiles + manifests K8s
- Documentation : README, architecture, référence API REST

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

back/.env.example

@@ -0,0 +1,13 @@
+# Database
+DATABASE_HOST=localhost
+DATABASE_PORT=5432
+DATABASE_USER=datacat
+DATABASE_PASSWORD=datacat
+DATABASE_NAME=datacat
+
+# App
+PORT=3000
+NODE_ENV=development
+
+# Docs generation
+DOCS_OUTPUT_DIR=/app/docs-output