fix: normalize WEBAPP_URL to prevent double-pathing (404 error)

index.js

@@ -12,7 +12,15 @@ const { setupBot } = require('./app/bot/bot');
 
 const app = express();
 const PORT = process.env.PORT || 7860;
-const WEBAPP_URL = process.env.WEBAPP_URL || 'https://your-domain.com';
+
+// Normalize WEBAPP_URL: remove trailing slash and common suffixes to avoid double-pathing in bot.js
+let WEBAPP_URL = (process.env.WEBAPP_URL || '').replace(/\/$/, '');
+if (WEBAPP_URL.endsWith('/app/index.html')) {
+    WEBAPP_URL = WEBAPP_URL.replace('/app/index.html', '');
+} else if (WEBAPP_URL.endsWith('/app')) {
+    WEBAPP_URL = WEBAPP_URL.replace('/app', '');
+}
+if (!WEBAPP_URL) WEBAPP_URL = `http://localhost:${PORT}`;
 
 // --- Express Server Setup ---
 app.use(cors());