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/loader.js

@@ -49,6 +49,21 @@ function ensureProgressBar() {
     // pushed off-viewport). hideProgress() reverts both.
     document.body.style.marginTop = '30px';
     document.body.style.height = 'calc(100vh - 30px)';
+    // Transparent overlay that blocks all mouse interaction while tests
+    // run. Tests dispatch synthetic events so they still work; only real
+    // user clicks/hovers are absorbed. Removed by hideProgress().
+    let shield = document.getElementById('test-shield');
+    if (!shield) {
+        shield = document.createElement('div');
+        shield.id = 'test-shield';
+        const ss = shield.style;
+        ss.setProperty('position', 'fixed', 'important');
+        ss.setProperty('inset', '30px 0 0 0', 'important');
+        ss.setProperty('z-index', '2147483646', 'important');
+        ss.setProperty('background', 'transparent', 'important');
+        ss.setProperty('cursor', 'not-allowed', 'important');
+        document.documentElement.appendChild(shield);
+    }
     const bar = document.createElement('div');
     bar.id = 'test-progress';
     const s = bar.style;