fix: final checkup review follow-ups

- i18n: the spreadsheet notice's feature words (charts, drawings, macros,
  pivot tables, external links) were bare, case-insensitive zh-CN keys, so
  the page translator also renamed a charts/ or macros/ folder in the Files
  panel and a case of that name in the case picker. They are now scoped
  'Spreadsheet feature: <word>' keys; warningText() falls back to the plain
  word when the scoped key has no translation (English, no i18n). Removing
  the bare keys closes this branch's regression. The older 'models' key has
  the same class of problem; it is left alone here, since adding
  .case-combobox-option-label to USER_TEXT_SELECTOR would also untranslate
  the picker's two action rows and still miss the title attribute.
- Spreadsheet notice bar: marked data-i18n-skip. It is written already
  translated, item by item, and ends with a number format's code, which the
  observer's t() over the whole line rewrote ({name}, "Codeman").
- Connection tile (Header Stats Style Tiles): applyLocalization() now repaints
  the indicator, so a switch back to English no longer leaves the Chinese
  value word in its data-i18n-skip span until the next keystroke or ACK.
- Tiles default: loadAppSettingsFromStorage() no longer caches the
  posture-dependent showTileGridButton default, so the init merge never
  persists it; a 2-in-1 first opened as a tablet gets the button once docked.
  Every reader still resolves the absent key through a fresh
  getDefaultSettings(), so phones stay OFF and desktops ON.
- Tile grid over a split: closeSplitPane() skips Pane A's closing resize only
  when Pane A becomes a tile. With mergeSplit false (Open group as tiles, a
  stored grid) a Pane A left out of the set gets its full width back before
  the main terminal parks, instead of keeping the split's half width.
- By-case tab strip on tablets and phones: with the boxes dissolved, the
  -<case> part of a generated name shows again, so w1-alpha and w1-beta no
  longer both read "w1".

Each new assertion fails against the previous source.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

test/spreadsheet-preview.test.ts

@@ -504,12 +504,64 @@ describe('spreadsheet preview text the user reads', () => {
         'View truncated to the first 2500 cells, Formula has no cached result, Unsupported cell value, ' +
         'Unsupported number format: {name}"x", 3 unsupported number formats'
     );
+    // The real English translator reads the feature words as plain words too,
+    // never as their scoped keys.
+    (window as any).codemanT = en;
+    expect(await notice()).toBe(english);
     (window as any).codemanT = zh;
     const chinese = await notice();
     // The format code is workbook text: kept as is ({name} is not a placeholder here).
     expect(chinese).toContain('不支持的数字格式: {name}"x"');
     expect(leftover(chinese.replace('{name}"x"', ''))).toEqual([]);
     expect(chinese.startsWith(`${zh('Some workbook features are not shown')}: 数据透视表, 外部链接, 图表`)).toBe(true);
+    // Through scoped keys only: the translator runs over the Files panel tree and
+    // the case picker too, where a bare 'charts' or 'macros' key would rename a
+    // Helm chart's charts/ or a dbt project's macros/ folder, or a case of that name.
+    const words = ['charts', 'drawings', 'pivot tables', 'external links', 'macros'];
+    expect(words.filter((word) => zh(word) !== word || zh(word.toUpperCase()) !== word.toUpperCase())).toEqual([]);
+  });
+
+  it('keeps the notice bar away from the page translator, so a format code is never rewritten', async () => {
+    // The real i18n.js in the renderer's own window. configure() walks the whole
+    // body with t(), which fills `{name}` and rebrands "Codeman" in every text
+    // node it reaches; the bar is written already translated, item by item, and
+    // ends with workbook text.
+    const { confirm, alert } = window;
+    const context = vm.createContext({
+      window,
+      document,
+      Node: window.Node,
+      NodeFilter: window.NodeFilter,
+      MutationObserver: window.MutationObserver,
+      console,
+    });
+    vm.runInContext(i18nSource, context, { filename: 'i18n.js' });
+    try {
+      const i18n = (window as any).CodemanI18n as { configure(o: object): void };
+      i18n.configure({ language: 'en', displayName: 'Acme' });
+      const worker = await openLoaded();
+      worker.emit({ ...metadata(), warnings: ['charts'] });
+      const request = worker.postMessage.mock.calls.at(-1)?.[0];
+      worker.emit({
+        type: 'tile',
+        requestId: request.requestId,
+        sheetId: '1',
+        cells: [],
+        warnings: ['Unsupported number format: {name}"Codeman"0'],
+      });
+      const bar = document.querySelector('.spreadsheet-preview-notice')!;
+      const written = 'Some workbook features are not shown: charts, Unsupported number format: {name}"Codeman"0';
+      expect(bar.textContent).toBe(written);
+      // A language or display-name change re-walks the page.
+      i18n.configure({ language: 'en', displayName: 'Acme' });
+      expect(bar.textContent).toBe(written);
+      expect(bar.hasAttribute('data-i18n-skip')).toBe(true);
+    } finally {
+      delete (window as any).CodemanI18n;
+      delete (window as any).codemanT;
+      window.confirm = confirm;
+      window.alert = alert;
+    }
   });
 
   it('the HTTP status line reads in Chinese with its status', async () => {