The Language section in Settings rendered a single-button dropdown
trigger that opened a floating menu. With one visible label and lots of
empty panel space, the layout misled users into thinking only one
language existed. Replace the dropdown trigger + portaled menu with an
inline tile grid that shows every locale at a glance and clicks
directly to switch.
Side effects of the new layout: the languageOpen / languageMenuRect
state, the dynamic placement effect, the resize-close effect, the
mousedown click-outside handler, and the languageRef are gone. The
global Escape handler no longer needs to guard against the menu being
open. CSS for .settings-language-picker, .settings-language-button,
.settings-language-menu, and .settings-language-option is replaced by
.settings-language-grid (auto-fill 180px minmax columns) +
.settings-language-tile.
Tests in SettingsDialog.execution.test.tsx that drove the dropdown
(click trigger → click menuitemradio → assert menu closed) are
rewritten to drive the tiles directly via the radio role.
Refs #1347
