feat(ui): vs-AI comms trim, overlay confirm button, recall-to-slot drag

- vs-AI: the comms hub drops the Chat tab (Dictionary only); a finished AI
  game has no comms at all, so its 💬 history-header entry is hidden too.
- Confirm-move ✅: redone as an absolute overlay pinned to the right edge (its
  right edge sits under the preview caption), so the rack keeps a fixed tile
  size — this reverts the tile-shrink that resized the letters at 6 tiles.
- Recall: dragging a placed tile back to the rack now drops it at the slot the
  pointer is over (drag-to-position, a gap opens), instead of snapping to its
  original slot; double-tap still recalls to the origin. New pure recallToSlot.

Tests: placement recallToSlot units; e2e recall-to-position; vs-AI comms e2e
updated. Docs: UI_DESIGN + FUNCTIONAL (+ru).

ui/src/game/Game.svelte

@@ -31,6 +31,7 @@
     placementFromHint,
     rackView,
     recallAt,
+    recallToSlot,
     reorderIndices,
     reset,
     toSubmit,
@@ -481,7 +482,12 @@
     if (c) {
       dropTarget = !board[c.row]?.[c.col] && !pendingMap.has(`${c.row},${c.col}`) ? c : null;
       reorderTo = null;
-    } else if (reorderDragId != null && overRack(e.clientY) && placement.pending.length === 0) {
+    } else if (
+      overRack(e.clientY) &&
+      // A rack-source reorder (only with a clean, pending-free rack) or a board tile dragged
+      // back to the rack — both preview the drop slot as a gap the dropped tile will fill.
+      ((reorderDragId != null && placement.pending.length === 0) || draggingPend != null)
+    ) {
       reorderTo = dropSlotAt(e.clientX);
       dropTarget = null;
     } else {
@@ -527,8 +533,15 @@
         // Dropped a placed tile on another board cell → relocate it there.
         relocatePending(di.src.row, di.src.col, cell.row, cell.col);
       } else if (di.src.from === 'board' && onRack) {
-        // Dropped a placed tile back onto the rack → recall it to its original slot.
-        placement = recallAt(placement, di.src.row, di.src.col);
+        // Dropped a placed tile back onto the rack → recall it to the drop slot the player aimed
+        // at (drag-to-position), or to its original slot when the drop is not over a gap.
+        if (to != null) {
+          const res = recallToSlot(placement, di.src.row, di.src.col, to);
+          rackIds = res.order.map((i) => rackIds[i] ?? i);
+          placement = res.placement;
+        } else {
+          placement = recallAt(placement, di.src.row, di.src.col);
+        }
         selected = null;
         recompute();
         scheduleDraftSave();
@@ -1114,9 +1127,13 @@
         <button class="hicon" onclick={() => (resignOpen = true)} disabled={waitingForOpponent} aria-label={t('game.dropGame')}>🏁</button>
       {/if}
       {#if !view.game.multipleWordsPerTurn}<span class="oneword-label">{t('game.oneWordRule')}</span>{/if}
-      <button class="hicon" onclick={() => navigate(`/game/${id}/chat`)} aria-label={t('game.chat')}>
-        {#key chatBlink}<span class="chat-ico" class:blink={chatBlink > 0 && !app.reduceMotion}>💬</span>{/key}
-      </button>
+      <!-- A finished AI game has no comms at all (no chat, and the dictionary closes with the
+           game), so the entry is dropped; an active AI game keeps it (it opens the dictionary). -->
+      {#if !(gameOver && view.game.vsAi)}
+        <button class="hicon" onclick={() => navigate(`/game/${id}/chat`)} aria-label={t('game.chat')}>
+          {#key chatBlink}<span class="chat-ico" class:blink={chatBlink > 0 && !app.reduceMotion}>💬</span>{/key}
+        </button>
+      {/if}
     </div>
     <div class="hgridwrap">
       <div class="hgrid" style="grid-template-columns: repeat({view.game.seats.length}, 1fr)">
@@ -1456,9 +1473,9 @@
     white-space: nowrap;
   }
   .rack-row {
+    position: relative;
     display: flex;
     flex: none;
-    gap: 8px;
     align-items: stretch;
     padding: 0 var(--pad) 6px;
   }
@@ -1471,11 +1488,17 @@
     min-width: 0;
   }
   /* A borderless icon button (like the tab bar), not a filled accent button — and disabled
-     while the pending word is known to be illegal. The glyph is right-aligned within its box so
-     its right edge lands under the right edge of the preview caption above it (both sit at
-     var(--pad) from the screen edge — .status and .rack-row share that padding). */
+     while the pending word is known to be illegal. It is an overlay, NOT a flex sibling of the
+     rack: the rack keeps the full row width with a fixed tile size (no reflow or tile resize
+     when a tile is staged), and the button is absolutely pinned over the slots a staged tile
+     frees on the right. Its right edge sits at var(--pad) — directly under the right edge of the
+     preview caption above (.status shares that padding). */
   .make {
-    min-width: 56px;
+    position: absolute;
+    right: var(--pad);
+    top: 0;
+    bottom: 6px;
+    width: 56px;
     background: none;
     color: var(--text);
     border: none;