feat(ui): batch of UI polish tweaks

- admin dashboard "Users" count excludes robots (CountUsers, humans only)
- lobby finished-game delete reveal: background matches header/tab-bar (--bg-elev)
- mobile: swipe up on the zoom-out board (no staged tiles) shuffles the rack
- lobby: status icons -25%, game-row top/bottom padding halved
- toast: info tier drifts up ~a tab-bar height while fading over 2s and dismisses
  on tap; error tier unchanged
- game: confirm-move button stays pinned at the right edge; rack tiles shrink to
  fit so a full rack never overflows onto it
- telegram: a successful invite-link redeem shows a welcome window pointing at the bot
- settings: remove the grid-lines toggle; the board is always a gapless checkerboard
- settings/comms hubs: the selected tab highlight wraps icon + label as a pill

Docs: UI_DESIGN (toast, board surface, selected tab), PLAN; e2e updated for the
removed grid-lines toggle.

ui/src/game/Game.svelte

@@ -813,6 +813,8 @@
   //  - closed: a downward "pull" opens the history, but only on the zoom-out board scrolled
   //    to its top — zoomed, the one-finger drag pans the board, and mid-scroll a downward drag
   //    is the stage's own vertical scroll (the conflict that once retired this open gesture).
+  //    On that same closed, zoom-out board an upward swipe with no staged tiles shuffles the
+  //    rack (a convenience mirror of the shuffle control).
   // Both genuinely set `historyOpen` (closing no longer merely scrolls the slid board out of
   // view, which left a stale-open state that made a follow-up score-bar tap "jump" the board).
   let stageEl = $state<HTMLDivElement>();
@@ -869,6 +871,14 @@
       if (-dy > 32) closeHistoryByGesture(); // enough upward travel
     } else if (dy > 40 && dy > Math.abs(dx) * 1.4) {
       openHistoryByGesture(); // a clear, vertical-dominant downward pull
+    } else if (-dy > 40 && -dy > Math.abs(dx) * 1.4 && placement.pending.length === 0) {
+      // The same closed-board arm, opposite direction: a clear upward swipe on the zoom-out
+      // board with no staged tiles shuffles the rack (a convenience mirror of the shuffle
+      // control). Disarm and swallow the synthesised click so it cannot also place a tile.
+      shuffle();
+      boardSwipe = null;
+      swallowClick = true;
+      setTimeout(() => (swallowClick = false), 120);
     }
   }
   function onBoardWrapUp(e: PointerEvent) {
@@ -1156,7 +1166,6 @@
       {landscape}
       {variant}
       labelMode={app.boardLabels}
-      lines={app.boardLines}
       locale={app.locale}
       {focus}
       {recenter}