fix: revert broken bottom-anchor, keep board full-screen with emote off board

The justify-content:flex-end approach left dead space at top.
Instead: keep flex:1 on board container (fills screen), use
align-items:flex-end so the canvas sits at the bottom of its
container. Emote button stays at fixed position off the board.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/js/modules/chess/scenes/game.js

@@ -97,7 +97,7 @@ export function mountGame(el, params) {
   }
 
   el.innerHTML = `
-    <div class="chess-layout" style="display:flex;flex-direction:column;height:100%;background:#1a1a2e;justify-content:flex-end;">
+    <div class="chess-layout" style="display:flex;flex-direction:column;height:100%;background:#1a1a2e;">
       <!-- Opponent Bar (compact — keep minimal at top) -->
       <div class="chess-bar" style="display:flex;align-items:center;justify-content:space-between;padding:4px 12px;background:#0f0f1e;">
         <div style="display:flex;align-items:center;gap:8px;">
@@ -116,7 +116,7 @@ export function mountGame(el, params) {
       </div>
 
       <!-- Board -->
-      <div id="board-container" style="display:flex;align-items:center;justify-content:center;padding:2px 4px;position:relative;">
+      <div id="board-container" style="flex:1;display:flex;align-items:flex-end;justify-content:center;padding:2px 4px;position:relative;min-height:0;">
         <div id="bot-thinking" style="display:none;position:absolute;top:8px;left:50%;transform:translateX(-50%);background:rgba(0,0,0,0.8);color:#E4AC38;padding:4px 12px;border-radius:12px;font-size:12px;font-weight:600;z-index:10;">
           ${t('game.thinking')} <span class="pulse">${emoji('thinking_dots', '●●●', 12)}</span>
         </div>

public/js/modules/ludo/scenes/game.js

@@ -76,12 +76,12 @@ export function mountGame(el, params) {
   });
 
   el.innerHTML = `
-    <div style="display:flex;flex-direction:column;height:100%;background:#1a1a2e;justify-content:flex-end;">
+    <div style="display:flex;flex-direction:column;height:100%;background:#1a1a2e;">
       <div style="display:flex;justify-content:space-between;padding:6px 12px;background:#0f0f1e;direction:ltr;">
         ${renderPanel(panels[1])}
         ${renderPanel(panels[2])}
       </div>
-      <div id="ludo-wrap" style="display:flex;align-items:center;justify-content:center;padding:4px 4px 8px;">
+      <div id="ludo-wrap" style="flex:1;display:flex;align-items:center;justify-content:center;padding:4px;min-height:0;">
       <div style="display:flex;justify-content:space-between;padding:6px 12px;background:#0f0f1e;direction:ltr;">
         ${renderPanel(panels[0])}
         ${renderPanel(panels[3])}