fix(overlay): keep popup pause working with Hachidori 0.4.0

Hachidori 0.4.0 closed its popup shadow root, so isHachidoriPopupOpen always
returned false. The popup never took over the subtitle hover pause, and moving
off the subtitle resumed playback with the popup open. Popup key and controller
routing read the same check. The sidebar kept working because its hold follows
the attention event instead of the pane.

The fork now publishes the pane state on the host element, and the renderer
reads that attribute instead of upstream's shadow root and CSS class. The unit
stubs modelled an open root and hid this, so test:dictionary:electron now drives
the real reader and asserts the attribute follows the pane.

scripts/check-hachidori-parser.cjs

@@ -8,6 +8,9 @@ const http = require('node:http');
 const root = path.resolve(__dirname, '..');
 const parser = require(path.join(root, 'dist/core/services/tokenizer/yomitan-parser-runtime.js'));
 const { writeStoredZip } = require(path.join(root, 'dist/shared/stored-zip.js'));
+const { HACHIDORI_POPUP_OPEN_SELECTOR } = require(
+  path.join(root, 'dist/renderer/yomitan-popup.js'),
+);
 const profile = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-hachidori-parser-'));
 
 protocol.registerSchemesAsPrivileged([
@@ -43,6 +46,58 @@ function fixture(name, title, bankName, entries, frequencyMode = 'rank-based') {
   return zipPath;
 }
 
+// The renderer's popup auto-pause and key routing read this marker because the
+// reader's shadow root is closed. Drives the real reader with real input, since
+// stubbed DOM tests cannot notice an upstream merge that changes what it exposes.
+async function assertPopupOpenMarkerFollowsPane(targetSession) {
+  const server = http.createServer((_request, response) => {
+    response.setHeader('Content-Type', 'text/html; charset=utf-8');
+    response.end(
+      '<!doctype html><p id="word" style="font-size:48px;margin:300px 0 0 100px">食べた</p>',
+    );
+  });
+  await new Promise((resolve) => server.listen(0, '127.0.0.1', resolve));
+  const page = new BrowserWindow({
+    width: 900,
+    height: 600,
+    show: true,
+    webPreferences: { session: targetSession, contextIsolation: true, nodeIntegration: false },
+  });
+  try {
+    await page.loadURL(`http://127.0.0.1:${server.address().port}/`);
+    const { webContents } = page;
+    const word = await webContents.executeJavaScript(
+      `(() => { const { x, y, height } = document.getElementById('word').getBoundingClientRect(); return { x, y, height }; })()`,
+    );
+    const repeatUntilMarker = async (expected, act) => {
+      const query = `document.querySelector(${JSON.stringify(HACHIDORI_POPUP_OPEN_SELECTOR)}) !== null`;
+      for (let attempt = 0; attempt < 100; attempt += 1) {
+        // Content scripts load asynchronously, so keep acting until the reader reacts.
+        act(attempt);
+        await new Promise((resolve) => setTimeout(resolve, 100));
+        if ((await webContents.executeJavaScript(query)) === expected) return;
+      }
+      assert.fail(`Hachidori popup-open marker never became ${expected}`);
+    };
+    page.focus();
+    webContents.focus();
+    await repeatUntilMarker(true, (attempt) =>
+      webContents.sendInputEvent({
+        type: 'mouseMove',
+        x: Math.round(word.x + 24) + (attempt % 2),
+        y: Math.round(word.y + word.height / 2),
+      }),
+    );
+    await repeatUntilMarker(false, () => {
+      webContents.sendInputEvent({ type: 'keyDown', keyCode: 'Escape' });
+      webContents.sendInputEvent({ type: 'keyUp', keyCode: 'Escape' });
+    });
+  } finally {
+    page.destroy();
+    await new Promise((resolve) => server.close(resolve));
+  }
+}
+
 app
   .whenReady()
   .then(async () => {
@@ -211,6 +266,7 @@ app
     assert.deepEqual(unmatched, []);
     assert.equal(await parser.getYomitanCurrentAnkiDeckName(deps, logger), 'Test Mining');
     assert.equal((await targetSession.extensions.getAllExtensions()).length, 1);
+    await assertPopupOpenMarkerFollowsPane(targetSession);
     assert.equal(
       await parser.syncYomitanDefaultAnkiServer('http://127.0.0.1:8765', deps, logger),
       true,