Fix PDF export font embedding and improve sync reliability

- Replace data URL loading with temporary HTML file to avoid URL length limits
- Embed font files as data URLs in print document CSS for offline rendering
- Add font asset registry for Merriweather, Crimson Pro, Roboto Serif, and Average
- Implement font file caching and blob-to-data-URL conversion
- Clean up temporary HTML file after PDF generation
- Fix sync to refresh notes after favorite status sync completes

electron/main.cjs

@@ -121,6 +121,11 @@ ipcMain.handle('desktop:export-pdf', async (event, payload) => {
     return { canceled: true };
   }
 
+  const tempHtmlPath = path.join(
+    app.getPath('temp'),
+    `nextcloud-notes-export-${Date.now()}-${Math.random().toString(36).slice(2, 8)}.html`
+  );
+
   const pdfWindow = new BrowserWindow({
     width: 960,
     height: 1100,
@@ -135,9 +140,8 @@ ipcMain.handle('desktop:export-pdf', async (event, payload) => {
   });
 
   try {
-    await pdfWindow.loadURL(
-      `data:text/html;charset=utf-8,${encodeURIComponent(payload.documentHtml)}`
-    );
+    await fs.writeFile(tempHtmlPath, payload.documentHtml, 'utf8');
+    await pdfWindow.loadFile(tempHtmlPath);
     await pdfWindow.webContents.executeJavaScript(waitForPrintDocument(), true);
 
     const pdfData = await pdfWindow.webContents.printToPDF({
@@ -152,6 +156,7 @@ ipcMain.handle('desktop:export-pdf', async (event, payload) => {
       filePath: saveResult.filePath,
     };
   } finally {
+    await fs.unlink(tempHtmlPath).catch(() => undefined);
     if (!pdfWindow.isDestroyed()) {
       pdfWindow.destroy();
     }