fix(a11y): reuse translated history-controls label key (Qodo PR review)

Qodo flagged: adding `aria-labelledby="editbar-history-label"` on
#history-controls overrode the `aria-label` that pad_mode.ts sets from
`pad.historyMode.controlsLabel`. That key is already translated in
multiple locales (en/de/nl/...); the new `pad.editor.toolbar.history`
key was English-only, so non-English users would regress from a
localized history-toolbar name to the English fallback.

Point the hidden label span at the existing translated key instead of
minting a new one, drop the new key from en.json, and update the
Playwright expectation to match the translated string ("Pad history
controls"). The aria-label that pad_mode.ts still writes to
#history-controls is now redundant (aria-labelledby wins) but harmless,
and leaving it preserves the runtime relocalization path.

Refs #7777

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: JohnMcLear

src/locales/en.json

@@ -364,7 +364,6 @@
   "pad.editor.keyboardHint": "Press Escape to exit the editor. Press Alt+F9 to access the toolbar.",
   "pad.editor.toolbar.formatting": "Formatting toolbar",
   "pad.editor.toolbar.actions": "Pad actions toolbar",
-  "pad.editor.toolbar.history": "History playback toolbar",
   "pad.editor.toolbar.showMore": "Show more toolbar buttons",
   "timeslider.toolbar.authors": "Authors:",
   "timeslider.toolbar.authorsList": "No Authors",

src/templates/pad.html

@@ -86,8 +86,12 @@
        accessible name via aria-labelledby. See ether/etherpad#7255. -->
   <span id="editbar-formatting-label" class="sr-only"
         data-l10n-id="pad.editor.toolbar.formatting">Formatting toolbar</span>
+  <!-- Reuses pad.historyMode.controlsLabel rather than minting a new key:
+       pad_mode.ts already set this as aria-label on #history-controls via JS,
+       and the existing key has translations in nl/de/etc. A new English-only
+       key would cause non-English locales to regress to fallback English. -->
   <span id="editbar-history-label" class="sr-only"
-        data-l10n-id="pad.editor.toolbar.history">History playback toolbar</span>
+        data-l10n-id="pad.historyMode.controlsLabel">Pad history controls</span>
   <span id="editbar-actions-label" class="sr-only"
         data-l10n-id="pad.editor.toolbar.actions">Pad actions toolbar</span>
   <span id="editbar-showmore-label" class="sr-only"

src/tests/frontend-new/specs/a11y_dialogs.spec.ts

@@ -161,7 +161,9 @@ test('editbar toolbars have role=toolbar with accessible names (#7255)', async (
   const cases: Array<[string, string, string]> = [
     ['.menu_left', 'editbar-formatting-label', 'Formatting toolbar'],
     ['.menu_right', 'editbar-actions-label', 'Pad actions toolbar'],
-    ['#history-controls', 'editbar-history-label', 'History playback toolbar'],
+    // History toolbar reuses pad.historyMode.controlsLabel (already
+    // translated in multiple locales) instead of a new English-only key.
+    ['#history-controls', 'editbar-history-label', 'Pad history controls'],
   ];
   for (const [sel, labelId, expected] of cases) {
     const toolbar = page.locator(sel);