feat(ui): move in-game status to the board — highlight, score badge, full-width rack

Remove the under-board status strip and relocate its signals:
- bag count -> a badge on the exchange/pass control + the foot of the move table
- whose-turn / win-lose -> a thin strip above the score plaques
- the tentative-move caption -> the board itself: staged tiles tint green (legal) or
  pink (illegal), the board tiles a formed word runs through go a shade darker, and an
  orange score badge sits on the main word (digit sized like a tile value, clamped on-board)

The word geometry (covered cells + badge anchor) is a new pure client-side helper
(ui/src/lib/formed.ts), independent of the move evaluator, so it works on the local or
network preview path alike; the badge's number still comes from the preview score.

Rack: a seven-column grid filling the tray width in both layouts — square, full-width
tiles — with the confirm control in the fixed 7th slot.

Settings: a touch-only "Zoom the board" toggle (default on, device-local) gates the
tile-placement auto-zoom; taking a hint while zoomed in now zooms out so the highlighted
hint word is never left off-screen.

Docs (FUNCTIONAL +_ru, UI_DESIGN, ARCHITECTURE) and e2e/unit tests updated.

ui/src/screens/Settings.svelte

@@ -5,6 +5,7 @@
     setLocalePref,
     setReduceMotion,
     setTheme,
+    setZoomBoard,
   } from '../lib/app.svelte';
   import { t, type Locale, type MessageKey } from '../lib/i18n/index.svelte';
   import type { ThemePref } from '../lib/theme';
@@ -15,6 +16,10 @@
   import { isStandalone } from '../lib/pwa';
   import InstallApp from '../components/InstallApp.svelte';
 
+  // The board-zoom toggle only makes sense on a touch device (the desktop / landscape layouts fit
+  // the whole board and never auto-zoom), so it is shown only for a coarse pointer.
+  const coarsePointer = typeof matchMedia !== 'undefined' && matchMedia('(pointer: coarse)').matches;
+
   // The offline toggle is for the installed web PWA with a confirmed email only: the service worker
   // that lets the app launch with no network runs only in a standalone web install (not a mini-app),
   // and a durable account (email) anchors the device-local games. Elsewhere the control is hidden.
@@ -102,6 +107,16 @@
         onchange={(e) => setReduceMotion(e.currentTarget.checked)}
       />
     </label>
+    {#if coarsePointer}
+      <label class="row">
+        <span>{t('settings.zoomBoard')}</span>
+        <input
+          type="checkbox"
+          checked={app.zoomBoard}
+          onchange={(e) => setZoomBoard(e.currentTarget.checked)}
+        />
+      </label>
+    {/if}
   </section>
 
   {#if offlineEligible}