fix(i18n): zh-CN for the Redraw toasts, and comments that named old defaults

Redraw (Ctrl+Shift+R and the header button) shows five literal toasts and a
size report on the main pane, a tile or the split's Pane B. None had a zh-CN
entry, including the two the final checkup's tile Redraw fix added, and
"Failed to restore terminal size" fell to the generic "Failed to" pattern,
which left English behind. They now translate, and the size report keeps its
numbers through a pattern rule. test/redraw-toast-i18n.test.ts reads the
toasts from restoreTerminalSize() itself, so a reworded one without an entry
fails.

Comments and docs that still described an older default:
- styles.css: the Tiles header button is no longer opt-in; it is on by default
  on desktop and off on phones and coarse-pointer tablets.
- terminal-ui.js: the desktop branch of getDefaultSettings is no longer always
  {}; what the comment needs is that it sets no copyStripMargin.
- docs/tile-grid-plan.md: the Tiles default bullet names the tablet default.
- docs/cli-registry.md: codex's footer is read in a two-row window since
  codex 0.162's hint row, not from its last row.

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

src/web/public/styles.css

@@ -2598,8 +2598,9 @@ html[data-tab-orientation='vertical'].tab-rail-compact
   display: none !important;
 }
 
-/* Tile grid header button: hidden by default (opt-in, `showTileGridButton`),
-   and hard-gated to desktop widths like Split (the backstop below). */
+/* Tile grid header button: shown unless `showTileGridButton` resolves off
+   (default ON on desktop, OFF on phones and on coarse-pointer tablets), and
+   hard-gated to desktop widths like Split (the backstop below). */
 .btn-tile-grid--hidden {
   display: none !important;
 }