Migrar backend a PostgreSQL + Node.js/Express con nuevas funcionalidades

Backend (water-api/):
- Crear API REST completa con Express + TypeScript
- Implementar autenticación JWT con refresh tokens
- CRUD completo para: projects, concentrators, meters, gateways, devices, users, roles
- Agregar validación con Zod para todas las entidades
- Implementar webhooks para The Things Stack (LoRaWAN)
- Agregar endpoint de lecturas con filtros y resumen de consumo
- Implementar carga masiva de medidores via Excel (.xlsx)

Frontend:
- Crear cliente HTTP con manejo automático de JWT y refresh
- Actualizar todas las APIs para usar nuevo backend
- Agregar sistema de autenticación real (login, logout, me)
- Agregar selector de tipo (LORA, LoRaWAN, Grandes) en concentradores y medidores
- Agregar campo Meter ID en medidores
- Crear modal de carga masiva para medidores
- Agregar página de consumo con gráficas y filtros
- Corregir carga de proyectos independiente de datos existentes

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

water-api/src/config/database.ts

@@ -0,0 +1,113 @@
+import { Pool, PoolClient, QueryResult, QueryResultRow } from 'pg';
+import config from './index';
+import logger from '../utils/logger';
+
+const pool = new Pool({
+  host: config.database.host,
+  port: config.database.port,
+  user: config.database.user,
+  password: config.database.password,
+  database: config.database.database,
+  ssl: config.database.ssl ? { rejectUnauthorized: false } : false,
+  max: config.database.maxConnections,
+  idleTimeoutMillis: config.database.idleTimeoutMs,
+  connectionTimeoutMillis: config.database.connectionTimeoutMs,
+});
+
+pool.on('connect', () => {
+  logger.debug('New client connected to the database pool');
+});
+
+pool.on('error', (err: Error) => {
+  logger.error('Unexpected error on idle database client', err);
+});
+
+pool.on('remove', () => {
+  logger.debug('Client removed from the database pool');
+});
+
+/**
+ * Execute a query on the database pool
+ * @param text - SQL query string
+ * @param params - Query parameters
+ * @returns Query result
+ */
+export const query = async <T extends QueryResultRow = QueryResultRow>(
+  text: string,
+  params?: unknown[]
+): Promise<QueryResult<T>> => {
+  const start = Date.now();
+
+  try {
+    const result = await pool.query<T>(text, params);
+    const duration = Date.now() - start;
+
+    logger.debug(`Query executed in ${duration}ms`, {
+      query: text,
+      rows: result.rowCount,
+    });
+
+    return result;
+  } catch (error) {
+    logger.error('Database query error', {
+      query: text,
+      error: error instanceof Error ? error.message : 'Unknown error',
+    });
+    throw error;
+  }
+};
+
+/**
+ * Get a client from the pool for transactions
+ * @returns Pool client
+ */
+export const getClient = async (): Promise<PoolClient> => {
+  try {
+    const client = await pool.connect();
+    logger.debug('Database client acquired from pool');
+    return client;
+  } catch (error) {
+    logger.error('Failed to get database client', {
+      error: error instanceof Error ? error.message : 'Unknown error',
+    });
+    throw error;
+  }
+};
+
+/**
+ * Test database connectivity
+ * @returns True if connection is successful, false otherwise
+ */
+export const testConnection = async (): Promise<boolean> => {
+  try {
+    const result = await pool.query('SELECT NOW()');
+    logger.info('Database connection successful', {
+      serverTime: result.rows[0]?.now,
+    });
+    return true;
+  } catch (error) {
+    logger.error('Database connection failed', {
+      error: error instanceof Error ? error.message : 'Unknown error',
+    });
+    return false;
+  }
+};
+
+/**
+ * Close all pool connections (for graceful shutdown)
+ */
+export const closePool = async (): Promise<void> => {
+  try {
+    await pool.end();
+    logger.info('Database pool closed');
+  } catch (error) {
+    logger.error('Error closing database pool', {
+      error: error instanceof Error ? error.message : 'Unknown error',
+    });
+    throw error;
+  }
+};
+
+export { pool };
+
+export default pool;