chore(docs): completar Fase 2 — requisitos y arquitectura

- Añade/actualiza `docs/requirements.md`, `docs/architecture.md`, `docs/api-integration.md`, `docs/data-model.md`
- Documenta criterios de aceptación y decisiones técnico-arquitectónicas
- Recomendación: añadir `docs/legal-considerations.md` (pendiente)

backend/package.json

@@ -0,0 +1,41 @@
+{
+  "name": "quasar-backend",
+  "version": "0.1.0",
+  "private": true,
+  "type": "commonjs",
+  "main": "dist/index.js",
+  "scripts": {
+    "dev": "ts-node-dev --respawn --transpile-only src/index.ts",
+    "build": "tsc -p tsconfig.json",
+    "start": "node dist/index.js",
+    "test": "vitest",
+    "prisma:generate": "prisma generate",
+    "prisma:migrate": "prisma migrate dev --name init",
+    "prisma:studio": "prisma studio",
+    "lint": "eslint \"src/**/*.{ts,js}\"",
+    "format": "prettier --write ."
+  },
+  "dependencies": {
+    "@fastify/cors": "^9.0.0",
+    "@fastify/helmet": "^11.0.0",
+    "@fastify/multipart": "^9.0.0",
+    "@fastify/rate-limit": "^9.0.0",
+    "@prisma/client": "5.22.0",
+    "dotenv": "^16.0.0",
+    "fastify": "^4.28.0",
+    "pino": "^8.0.0"
+  },
+  "devDependencies": {
+    "@types/node": "^18.0.0",
+    "eslint": "^8.0.0",
+    "prettier": "^2.8.0",
+    "prisma": "5.22.0",
+    "ts-node-dev": "^2.0.0",
+    "typescript": "^5.2.0",
+    "vitest": "^0.31.0"
+  },
+  "metadata": {
+    "autor": "GitHub Copilot",
+    "ultima_actualizacion": "2026-02-07"
+  }
+}