feat: support showWatermark parameter for dynamic footer

server.js

@@ -19,11 +19,13 @@ app.get('/', (req, res) => {
 app.post('/api/generate_pdf', async (req, res) => {
   let browser = null;
   try {
-    const { html } = req.body;
+    const { html, showWatermark } = req.body;
     if (!html) {
       return res.status(400).json({ error: 'Missing html content' });
     }
 
+    const brandText = showWatermark !== false ? 'Powered by XWX AI Chat Exporter' : '';
+
     // Launch Chrome
     // We use the installed 'chromium' from apt-get
     browser = await puppeteer.launch({
@@ -58,7 +60,7 @@ app.post('/api/generate_pdf', async (req, res) => {
       headerTemplate: '<div></div>', // Empty header
       footerTemplate: `
         <div style="font-size: 10px; font-family: Arial, sans-serif; color: #999; width: 100%; padding: 0 15mm; display: flex; justify-content: space-between; align-items: center;">
-            <div style="flex: 1; text-align: left;">Powered by XWX AI Chat Exporter</div>
+            <div style="flex: 1; text-align: left;">${brandText}</div>
             <div style="flex: 1; text-align: right;"><span class="pageNumber"></span> / <span class="totalPages"></span></div>
         </div>
       `,