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/src/app.js

@@ -0,0 +1,42 @@
+import express from 'express';
+import cors from 'cors';
+import helmet from 'helmet';
+import { env } from './config/env.js';
+import { notFoundHandler, errorHandler } from './middleware/errorHandler.js';
+
+import authRoutes from './modules/auth/routes.js';
+import usersRoutes from './modules/users/routes.js';
+import departmentsRoutes from './modules/departments/routes.js';
+import catalogsRoutes from './modules/catalogs/routes.js';
+import projectsRoutes from './modules/projects/routes.js';
+import activitiesRoutes from './modules/activities/routes.js';
+import subtasksRoutes from './modules/subtasks/routes.js';
+import commentsRoutes from './modules/comments/routes.js';
+import attachmentsRoutes from './modules/attachments/routes.js';
+import notificationsRoutes from './modules/notifications/routes.js';
+import dashboardRoutes from './modules/dashboard/routes.js';
+import auditRoutes from './modules/audit/routes.js';
+
+export const app = express();
+
+app.use(helmet({ contentSecurityPolicy: false }));
+app.use(cors({ origin: env.corsOrigin, credentials: true }));
+app.use(express.json({ limit: '2mb' }));
+
+app.get('/health', (req, res) => res.json({ success: true, data: { status: 'ok' }, error: null }));
+
+app.use('/api/auth', authRoutes);
+app.use('/api/users', usersRoutes);
+app.use('/api/departments', departmentsRoutes);
+app.use('/api/catalogs', catalogsRoutes);
+app.use('/api/projects', projectsRoutes);
+app.use('/api/activities', activitiesRoutes);
+app.use('/api', subtasksRoutes);
+app.use('/api/comments', commentsRoutes);
+app.use('/api/attachments', attachmentsRoutes);
+app.use('/api/notifications', notificationsRoutes);
+app.use('/api/dashboard', dashboardRoutes);
+app.use('/api/audit', auditRoutes);
+
+app.use(notFoundHandler);
+app.use(errorHandler);