test: move the non-contiguous range copy test onto the Clipboard API transport

The multi-range gap test arrived with the `hidden` column work on next-v6 and
stubbed `window.clipboardData` - the legacy IE transport this branch removes - then
asserted synchronously. Against the async Clipboard API it captured nothing and the
copied text read back as empty.

It now stubs `navigator.clipboard` the same way the other tests in this spec do, and
retries the assertion because the copy handler awaits the write. The expectation is
unchanged, so it still covers what it was written for: gaps preserved between two
non-contiguous ranges.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: 6pac-ai

cypress/e2e/example-excel-compatible-spreadsheet.cy.ts

@@ -90,28 +90,29 @@ describe('Example - Excel-compatible spreadsheet and Cell Selection', { retries:
   });
 
   it('should preserve gaps when copying multiple non-contiguous ranges', () => {
+    const store = { text: '' };
+
     cy.window().then((win: any) => {
-      const previousClipboardData = win.clipboardData;
-      let copiedText = '';
-      Object.defineProperty(win, 'clipboardData', {
+      Object.defineProperty(win.navigator, 'clipboard', {
         configurable: true,
         value: {
-          setData: (_format: string, text: string) => { copiedText = text; }
-        }
+          writeText: (t: string) => { store.text = t; return Promise.resolve(); },
+          readText: () => Promise.resolve(store.text),
+        },
       });
 
-    const selectionModel = win.grid.getSelectionModel();
-    selectionModel.setSelectedRanges([
-      new win.Slick.Range(1, 1, 1, 2),
-      new win.Slick.Range(2, 3, 2, 3)
-    ]);
+      const selectionModel = win.grid.getSelectionModel();
+      selectionModel.setSelectedRanges([
+        new win.Slick.Range(1, 1, 1, 2),
+        new win.Slick.Range(2, 3, 2, 3)
+      ]);
       const copyEvent = new win.KeyboardEvent('keydown', { key: 'c', code: 'KeyC', ctrlKey: true, bubbles: true });
       Object.defineProperty(copyEvent, 'which', { value: 67 });
       win.grid.getCanvasNode().dispatchEvent(copyEvent);
-
-    expect(copiedText).to.eq('1\t2\t\r\n\t\t4\r\n');
-      Object.defineProperty(win, 'clipboardData', { configurable: true, value: previousClipboardData });
     });
+
+    // the copy handler awaits the clipboard write, so retry until the stub has the text
+    cy.wrap(store).its('text').should('eq', '1\t2\t\r\n\t\t4\r\n');
   });
 });
 });