focus: restore body focus on overlay close, test shield, ESC closes results

Focus restoration:
* editor.js closeModal(): blur activeElement after the close so board
  shortcuts (arrows, bare keys) work immediately without clicking.
* detail.js closeDetail(): same blur, skipped when openedFromSearch
  (search input should keep focus in that case).
* search.js closeSearch(): blur after removing .open.
* calendar.js closeCalendar(): blur after closeDayPopup.
All four check activeElement !== body before blurring to avoid no-ops.

Test shield (loader.js):
* ensureProgressBar() now also creates #test-shield — a transparent
  fixed overlay (z-index one below the progress bar) covering the
  viewport below the bar. Blocks all real mouse interaction while
  tests run; synthetic events from the test suite still work because
  they bypass pointer-events. cursor:not-allowed as visual feedback.
  Removed by hideProgress() alongside the progress bar.

ESC closes test results (runner.js):
* The existing keydown listener now also handles Escape when the
  test-panel is visible. stopPropagation prevents the app's Escape
  chain from firing a second close underneath.

Tests (board.test.js):
* New describe "Board: Focus restoration after overlay close":
  - closing the editor returns focus to body
  - closing the detail view returns focus to body
  - closing search returns focus to body
  - arrow keys work after editor round-trip (enter → enter → escape)
    — the exact flow the user reported as broken. Dispatches
    ArrowDown → Enter (detail) → Enter (editor) → Escape (close) →
    asserts body focus → ArrowDown → asserts .card-focused exists.
* Fixed .not.toBe() → (x !== y).toBe(true) since the custom runner
  doesn't have a .not chain.

chore: bump version to 0.9.14

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

public/plugins/tests/board.test.js

@@ -124,3 +124,63 @@ describe('Board: Card Create & Delete', () => {
         }
     });
 });
+
+describe('Board: Focus restoration after overlay close', () => {
+    afterEach(() => closeAll());
+
+    it('closing the editor returns focus to body', async () => {
+        click('#add-btn');
+        await sleep(200);
+        // Editor is open — focus should be inside the modal (title input)
+        expect(document.activeElement !== document.body).toBe(true);
+        click('#modal-cancel');
+        await sleep(200);
+        expect(document.activeElement).toBe(document.body);
+    });
+
+    it('closing the detail view returns focus to body', async () => {
+        const card = $('#board [data-id]');
+        if (!card) return;
+        click(card);
+        await sleep(300);
+        if (!$('#detail')?.classList.contains('open')) return;
+        click('#detail-close');
+        await sleep(200);
+        expect(document.activeElement).toBe(document.body);
+    });
+
+    it('closing search returns focus to body', async () => {
+        click('#search-btn');
+        await sleep(200);
+        if (!$('#search')?.classList.contains('open')) return;
+        expect(document.activeElement?.id).toBe('search-input');
+        document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
+        await sleep(200);
+        expect(document.activeElement).toBe(document.body);
+    });
+
+    it('arrow keys work after editor round-trip (enter → enter → escape)', async () => {
+        const card = $('#board [data-id]');
+        if (!card) return;
+        // Focus a card
+        document.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowDown', bubbles: true }));
+        await sleep(100);
+        if (!document.querySelector('#board .card-focused')) return;
+        // Enter → detail
+        document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Enter', bubbles: true }));
+        await sleep(300);
+        if (!$('#detail')?.classList.contains('open')) return;
+        // Enter → close detail, open editor
+        document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Enter', bubbles: true }));
+        await sleep(300);
+        if (!$('#modal')?.classList.contains('open')) return;
+        // Escape → close editor
+        document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
+        await sleep(200);
+        expect(document.activeElement).toBe(document.body);
+        // Arrows should work again
+        document.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowDown', bubbles: true }));
+        await sleep(100);
+        expect(document.querySelector('#board .card-focused')).toExist();
+    });
+});