chore: estructura inicial del MVP

Backend (Express + MariaDB) y frontend (React + Vite, identidad Fluent/Windows) con el
nucleo funcional: seguridad, organizacion, proyectos, actividades, subtareas, dependencias,
dashboard, calendario, gantt, comentarios, adjuntos, notificaciones in-app y catalogos.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "project-linkedcorp-backend",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "main": "src/server.js",
+  "scripts": {
+    "dev": "node --watch src/server.js",
+    "start": "node src/server.js",
+    "migrate": "node src/scripts/migrate-db.js",
+    "seed": "node src/scripts/seed-db.js"
+  },
+  "dependencies": {
+    "bcryptjs": "^2.4.3",
+    "cors": "^2.8.5",
+    "dotenv": "^16.4.5",
+    "express": "^4.19.2",
+    "express-rate-limit": "^7.4.0",
+    "helmet": "^7.1.0",
+    "jsonwebtoken": "^9.0.2",
+    "multer": "^2.3.0",
+    "mysql2": "^3.11.0"
+  }
+}