Stage 17 round 6 (cluster 1): profile, tap flash, variant naming, chat/nudge by turn

- Profile: drop the hint-balance line.
- Board: no mobile tap flash on a cell tap (-webkit-tap-highlight-color: transparent),
  matching the web click; the only intentional cell animation stays the last-word flash.
- Variant names keyed by the game's alphabet, not the UI language: english -> Scrabble
  always, russian_scrabble -> Скрэббл always (unlocalized, never collide), erudit localized.
- Chat/nudge are mutually exclusive by turn: the message field + Send show on your turn,
  the nudge replaces them on the opponent's turn; while the nudge cooldown is active the
  button is disabled with a grey 'awaiting reply' caption to its left.

ui/src/game/Chat.svelte

@@ -6,16 +6,20 @@
     messages,
     myId,
     busy,
-    canNudge = true,
+    myTurn = false,
+    nudgeOnCooldown = false,
     onsend,
     onnudge,
   }: {
     messages: ChatMessage[];
     myId: string;
     busy: boolean;
-    // Nudging only makes sense while waiting on the opponent; it is disabled on the
-    // player's own turn (there is no one to hurry along).
-    canNudge?: boolean;
+    // Chat and nudge are mutually exclusive by turn (Stage 17): on the player's own turn the
+    // message field + send are shown (and nudging makes no sense — there is no one to
+    // hurry); on the opponent's turn only the nudge button shows. While the hourly nudge
+    // cooldown is active the nudge is disabled with an "awaiting reply" caption.
+    myTurn?: boolean;
+    nudgeOnCooldown?: boolean;
     onsend: (text: string) => void;
     onnudge: () => void;
   } = $props();
@@ -44,14 +48,18 @@
     {/each}
   </div>
   <div class="input">
-    <input
-      maxlength="60"
-      placeholder={t('chat.placeholder')}
-      bind:value={text}
-      onkeydown={(e) => e.key === 'Enter' && send()}
-    />
-    <button class="iconbtn" onclick={send} disabled={busy} aria-label={t('chat.send')}>⬆️</button>
-    <button class="iconbtn" onclick={onnudge} disabled={busy || !canNudge} aria-label={t('chat.nudgeAction')}>🛎️</button>
+    {#if myTurn}
+      <input
+        maxlength="60"
+        placeholder={t('chat.placeholder')}
+        bind:value={text}
+        onkeydown={(e) => e.key === 'Enter' && send()}
+      />
+      <button class="iconbtn" onclick={send} disabled={busy} aria-label={t('chat.send')}>⬆️</button>
+    {:else}
+      {#if nudgeOnCooldown}<span class="cooldown">{t('chat.awaitingReply')}</span>{/if}
+      <button class="iconbtn" onclick={onnudge} disabled={busy || nudgeOnCooldown} aria-label={t('chat.nudgeAction')}>🛎️</button>
+    {/if}
   </div>
 </div>
 
@@ -99,6 +107,14 @@
   .input {
     display: flex;
     gap: 6px;
+    align-items: center;
+  }
+  /* The cooldown caption sits to the left of the disabled nudge button. */
+  .cooldown {
+    flex: 1;
+    text-align: right;
+    color: var(--text-muted);
+    font-size: 0.85rem;
   }
   .input input {
     flex: 1;