feat(auth): login JWT en API y las 4 apps

- Modelo Usuario + seed desde lista de vendedores (18 usuarios, bcrypt cost 12)
- POST /api/auth/login + /api/auth/me; middleware Bearer en todo /api
  excepto health, login y webhook Monday; flag AUTH_ENABLED
- Username = nombre completo normalizado (case/acentos insensible),
  password inicial Frasa2026, admin vía ADMIN_PASSWORD
- Apps: LoginScreen + AuthGate (StudioBlank), token en localStorage,
  header Authorization en todas las llamadas, logout en 401
- Tests: api 136, cotizador 71, alta 65, cobranza 71, agente-ia 13, landing 4

api-gateway/package.json

@@ -13,22 +13,27 @@
     "start": "node dist/index.js",
     "test": "vitest run",
     "seed:ai": "tsx scripts/seed-ai.ts",
+    "seed:usuarios": "tsx scripts/seed-usuarios.ts",
     "setup:crm": "tsx scripts/setup-crm.ts",
     "sync:desarrollos": "tsx scripts/sync-desarrollos.ts",
     "prisma:migrate": "prisma migrate dev"
   },
   "dependencies": {
     "@prisma/client": "^6.14.0",
+    "bcryptjs": "^3.0.3",
     "cors": "^2.8.5",
     "dotenv": "^16.4.5",
     "express": "^5.1.0",
+    "jsonwebtoken": "^9.0.3",
     "multer": "^2.0.2",
     "node-cron": "^4.6.0",
     "zod": "^3.25.76"
   },
   "devDependencies": {
+    "@types/bcryptjs": "^2.4.6",
     "@types/cors": "^2.8.19",
     "@types/express": "^5.0.3",
+    "@types/jsonwebtoken": "^9.0.10",
     "@types/multer": "^2.0.0",
     "@types/node": "^22.15.0",
     "@types/node-cron": "^3.0.11",