test(behavior): add list marker font inheritance test (SD-1387)

Verifies that when a user creates a numbered list, changes the font,
and presses Enter to add a new item, the new marker inherits the font
from the previous paragraph instead of falling back to document defaults.

Author: caio-pizzol

tests/behavior/tests/lists/list-marker-font-inheritance.spec.ts

@@ -0,0 +1,63 @@
+import { test, expect } from '../../fixtures/superdoc.js';
+import { createOrderedList, LIST_MARKER_SELECTOR } from '../../helpers/lists.js';
+
+test.use({ config: { toolbar: 'full' } });
+
+/**
+ * Helper: select all text in the document and change font via toolbar.
+ */
+async function selectAllAndChangeFont(
+  superdoc: Parameters<Parameters<typeof test>[2]>[0]['superdoc'],
+  fontName: string,
+) {
+  await superdoc.selectAll();
+  await superdoc.waitForStable();
+
+  // Open font family dropdown and pick the font
+  await superdoc.page.locator('[data-item="btn-fontFamily"]').click();
+  await superdoc.page.locator('[data-item="btn-fontFamily-option"]').filter({ hasText: fontName }).click();
+  await superdoc.waitForStable();
+}
+
+/**
+ * Helper: get the computed font-family of a list marker by line index.
+ * DomPainter renders markers as .superdoc-paragraph-marker — CSS is the
+ * authoritative source for visual font since the layout engine sets it.
+ */
+async function getMarkerFontFamily(
+  superdoc: Parameters<Parameters<typeof test>[2]>[0]['superdoc'],
+  markerIndex: number,
+): Promise<string> {
+  return superdoc.page.evaluate((idx) => {
+    const markers = document.querySelectorAll('.superdoc-paragraph-marker');
+    const marker = markers[idx];
+    if (!marker) throw new Error(`Marker at index ${idx} not found`);
+    return getComputedStyle(marker).fontFamily;
+  }, markerIndex);
+}
+
+test('new list item marker inherits font from previous paragraph', async ({ superdoc }) => {
+  // Create a 2-item ordered list and change font to Georgia
+  await createOrderedList(superdoc, ['first item', 'second item']);
+  await superdoc.waitForStable();
+  await selectAllAndChangeFont(superdoc, 'Georgia');
+
+  // Verify markers are in Georgia
+  const markerFontBefore = await getMarkerFontFamily(superdoc, 0);
+  expect(markerFontBefore.toLowerCase()).toContain('georgia');
+
+  // Place cursor at end of last item and press Enter to create a new empty item
+  const pos = await superdoc.findTextPos('second item');
+  await superdoc.setTextSelection(pos + 'second item'.length);
+  await superdoc.waitForStable();
+  await superdoc.newLine();
+  await superdoc.waitForStable();
+
+  // Should now have 3 markers
+  const markerCount = await superdoc.page.locator(LIST_MARKER_SELECTOR).count();
+  expect(markerCount).toBe(3);
+
+  // The new (third) marker should inherit Georgia, not fall back to default
+  const newMarkerFont = await getMarkerFontFamily(superdoc, 2);
+  expect(newMarkerFont.toLowerCase()).toContain('georgia');
+});