Add backend config

backend/src/config.js

@@ -0,0 +1,40 @@
+import dotenv from 'dotenv';
+
+dotenv.config();
+
+const bool = (value, fallback = false) => {
+  if (value === undefined || value === null || value === '') return fallback;
+  return ['1', 'true', 'yes', 'on'].includes(String(value).toLowerCase());
+};
+
+export const config = {
+  app: {
+    env: process.env.APP_ENV || 'development',
+    host: process.env.APP_HOST || '127.0.0.1',
+    port: Number(process.env.APP_PORT || 3000),
+    trustProxy: bool(process.env.TRUST_PROXY, true),
+    publicApiUrl: process.env.PUBLIC_API_URL || 'http://localhost:3000',
+    publicWsUrl: process.env.PUBLIC_WS_URL || 'ws://localhost:3000/ws'
+  },
+  db: {
+    path: process.env.DATABASE_PATH || './data/chat.sqlite'
+  },
+  cors: {
+    adminOrigin: process.env.ADMIN_ORIGIN || 'http://localhost:5173',
+    widgetOrigin: process.env.WIDGET_ORIGIN || 'http://localhost:5174'
+  },
+  telegram: {
+    token: process.env.TELEGRAM_BOT_TOKEN || '',
+    proxy: {
+      enabled: bool(process.env.TELEGRAM_PROXY_ENABLED, false),
+      type: process.env.TELEGRAM_PROXY_TYPE || 'socks5',
+      host: process.env.TELEGRAM_PROXY_HOST || '127.0.0.1',
+      port: Number(process.env.TELEGRAM_PROXY_PORT || 9050),
+      username: process.env.TELEGRAM_PROXY_USERNAME || '',
+      password: process.env.TELEGRAM_PROXY_PASSWORD || ''
+    }
+  },
+  auth: {
+    jwtSecret: process.env.JWT_SECRET || 'change-me'
+  }
+};