```

feat: add file block with drag-and-drop support

- Implemented file upload block with preview support for images, videos, PDFs, text, code, and DOCX files
- Added drag-and-drop directive for files with visual drop indicators in root and column contexts
- Created file icon component with FontAwesome integration for 50+ file type icons
```

e2e/file-block.spec.ts

@@ -0,0 +1,15 @@
+import { test, expect } from '@playwright/test';
+
+// Basic smoke test to ensure the editor page loads and the File tile exists
+// Note: Full OS file picker automation is not performed here; this verifies UI wiring only.
+
+test.describe('File Block - Smoke', () => {
+  test('palette opens and shows File item', async ({ page }) => {
+    await page.goto('http://localhost:4200/tests/nimbus-editor');
+    // Open palette via slash keyboard would be flaky; instead click menu button present in header
+    await page.keyboard.press('/');
+    await page.waitForTimeout(300);
+    const fileItem = page.getByText('File', { exact: true });
+    await expect(fileItem).toBeVisible();
+  });
+});