Implement Texas Hold'em play: dealing, betting, side pots, showdown

- Hand engine (server/hand.js): crypto-shuffled deck kept server-side,
  blinds (heads-up button = SB), min-raise rules incl. incomplete all-in,
  uncalled bet refunds, side pots, split pots, all-in runout
- Hand evaluator (server/cards.js) and node:test suite (npm test)
- Table flow: hands auto-continue after host START, 30s action clock
  (timeout = check/fold + sit out), sit out / sit in, rebuy, mid-hand leave
  folds and keeps the seat reserved until the hand ends, pause freezes all clocks
- Only each player's own hole cards are sent until a showdown/runout reveal;
  all actions validated server-side
- Play UI: board, hole cards, bets, action tags, turn timer, raise panel with
  presets, showdown results with winning cards highlighted, compact 7+ layout
- Remove the host crown and the temporary "next phase" control

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

public/table.html

@@ -20,7 +20,6 @@
 
     <div class="host-controls" id="host-controls" hidden>
       <button class="btn btn-green" id="start">START ▶</button>
-      <button class="btn btn-dark" id="next-phase" title="プレイ未実装のため手動でフェーズを進めます">次へ（仮）</button>
       <button class="btn btn-dark" id="pause">一時停止</button>
     </div>
     <div class="host-spacer" id="host-spacer"></div>
@@ -39,22 +38,59 @@
       <div class="felt">
         <div class="pot-label">POT</div>
         <div class="pot" id="pot">$0</div>
-        <div class="phase" id="phase">WAITING</div>
-        <div class="hand-no" id="hand-no"></div>
+        <div class="board" id="board"></div>
+        <div class="phase"><span id="phase">WAITING</span><span class="hand-no" id="hand-no"></span></div>
+        <div class="result" id="result" hidden></div>
       </div>
       <div id="seats"></div>
     </div>
 
-    <div class="spectator-note" id="spectator-note" hidden>満席のため観戦中です</div>
+    <div class="spectator-note" id="spectator-note" hidden>
+      <span id="spectator-text">満席のため観戦中です</span>
+      <button class="btn btn-orange btn-sm" id="take-seat" hidden>空席に座る</button>
+    </div>
   </main>
 
   <div class="action-bar" id="action-bar" hidden>
+    <div class="turn-progress" id="turn-progress" hidden><i id="turn-bar"></i></div>
     <div class="inner">
-      <div class="my-stack"><span class="wallet">👛</span><span id="my-stack">$0</span></div>
-      <div class="actions">
-        <button class="btn" disabled>Fold</button>
-        <button class="btn" disabled>Check</button>
-        <button class="btn" disabled>Raise</button>
+      <div class="me-row">
+        <div class="my-cards" id="my-cards"></div>
+        <div class="me-info">
+          <div class="my-stack"><span class="wallet">👛</span><span id="my-stack">$0</span></div>
+          <div class="me-sub"><span class="my-hand" id="my-hand"></span><span id="my-net"></span></div>
+        </div>
+        <button class="btn btn-ghost btn-sm" id="sit-out" title="次のハンドから参加しません">離席</button>
+      </div>
+
+      <div class="status-line" id="status-line"></div>
+
+      <div class="raise-panel" id="raise-panel" hidden>
+        <div class="presets" id="presets">
+          <button class="btn btn-dark btn-sm" data-preset="min">Min</button>
+          <button class="btn btn-dark btn-sm" data-preset="half">½</button>
+          <button class="btn btn-dark btn-sm" data-preset="threeq">¾</button>
+          <button class="btn btn-dark btn-sm" data-preset="pot">Pot</button>
+          <button class="btn btn-dark btn-sm" data-preset="max">All-in</button>
+        </div>
+        <div class="raise-row">
+          <input type="range" id="raise-range" aria-label="レイズ額">
+          <input type="number" id="raise-amount" inputmode="numeric" aria-label="レイズ額">
+        </div>
+      </div>
+
+      <div class="actions" id="actions">
+        <button class="btn act-fold" id="act-fold" disabled>Fold</button>
+        <button class="btn act-call" id="act-call" disabled>Check</button>
+        <button class="btn act-raise" id="act-raise" disabled>Raise</button>
+      </div>
+      <div class="actions raising" id="raise-actions" hidden>
+        <button class="btn btn-dark" id="raise-cancel">戻る</button>
+        <button class="btn act-raise" id="raise-confirm">Raise</button>
+      </div>
+      <div class="actions single" id="alt-actions" hidden>
+        <button class="btn btn-orange" id="sit-in">復帰する</button>
+        <button class="btn btn-blue" id="rebuy">リバイ</button>
       </div>
     </div>
   </div>