✅(frontend) add pdf export regression test with embedded image fixtures

adds base64 png/jpg/svg image fixtures to stabilize pdf export snapshots

Signed-off-by: Cyril <c.gromoff@gmail.com>

Author: Ovgodd

src/frontend/apps/e2e/__tests__/app-impress/assets/content.txt

@@ -0,0 +1,29 @@
+//utilitary script to print the datauris of the targeted assets
+
+const fs = require('fs');
+const path = require('path');
+
+const ASSETS_ROOT = path.resolve(__dirname, '__tests__/app-impress/assets');
+
+function saveDataUrl(file, mime, outName) {
+    const abs = path.join(ASSETS_ROOT, file);
+    const base64 = fs.readFileSync(abs).toString('base64');
+    const dataUrl = `data:${mime};base64,${base64}`;
+    const outPath = path.join(ASSETS_ROOT, outName);
+    fs.writeFileSync(outPath, dataUrl, 'utf8');
+    console.log(`Wrote ${outName}`);
+}
+
+// PNG
+saveDataUrl('panopng.png', 'image/png', 'pano-png-dataurl.txt');
+
+// JPG
+saveDataUrl('panojpg.jpeg', 'image/jpeg', 'pano-jpg-dataurl.txt');
+
+// SVG
+const svgPath = path.join(ASSETS_ROOT, 'test.svg');
+const svgText = fs.readFileSync(svgPath, 'utf8');
+const svgDataUrl =
+    'data:image/svg+xml;base64,' + Buffer.from(svgText).toString('base64');
+fs.writeFileSync(path.join(ASSETS_ROOT, 'test-svg-dataurl.txt'), svgDataUrl, 'utf8');
+console.log('Wrote test-svg-dataurl.txt');