test(library): drive every More menu key and drop its unused close export (#512)

CI's coverage gate found more-menu.mjs functions at 71.42% (floor 80): the
ArrowUp-on-button, ArrowUp/Home/End-in-menu and Tab paths were untested and
an unused close() export counted as uncovered. The delete spec now drives
them; measured locally on that spec: 100% lines and functions.

tests/browser/workspace-library-delete.spec.mjs

@@ -480,8 +480,12 @@ test('the prompt page\'s More menu opens Delete prompt…, by mouse and keyboard
     await page.keyboard.press('ArrowDown');await expect(item).toBeFocused();
     await page.keyboard.press('Escape');
     await expect(moreMenu(page)).toBeHidden();await expect(more(page)).toBeFocused();await expect(more(page)).toHaveAttribute('aria-expanded','false');
+    // ArrowUp opens on the last item; ArrowUp, Home and End move within it (one item here); Tab closes it.
+    await page.keyboard.press('ArrowUp');await expect(item).toBeFocused();
+    for(const key of ['ArrowUp','Home','End']) {await page.keyboard.press(key);await expect(item).toBeFocused();}
+    await page.keyboard.press('Tab');await expect(moreMenu(page)).toBeHidden();await expect(more(page)).toHaveAttribute('aria-expanded','false');
     // Space opens too; an outside press closes it.
-    await page.keyboard.press(' ');await expect(item).toBeFocused();
+    await more(page).focus();await page.keyboard.press(' ');await expect(item).toBeFocused();
     await page.locator('#workspace-main h1').click();await expect(moreMenu(page)).toBeHidden();
     // Choosing it opens the page's review, titled for this prompt; Cancel returns focus to ⋯.
     await more(page).click();await item.click();

web/js/workspace/more-menu.mjs

@@ -7,7 +7,7 @@ import { createButton } from '../shared/toolkit/core.js';
  * returns focus to the button; Tab, an outside pointer press or choosing an item closes it. A held button
  * (`aria-disabled`) or a disabled one opens nothing. Listeners live on `scope`.
  *
- * `items`: `[{ label, danger, onSelect }]`. Returns `{ element, button, close, setDisabled(disabled) }`.
+ * `items`: `[{ label, danger, onSelect }]`. Returns `{ element, button, setDisabled(disabled) }`.
  */
 let menus = 0;
 export function createMoreMenu({ scope, label, items }) {
@@ -80,7 +80,6 @@ export function createMoreMenu({ scope, label, items }) {
     return {
         element,
         button,
-        close: () => close(false),
         setDisabled(disabled) { button.disabled = disabled; if (disabled) close(false); },
     };
 }