Fix widow/play bugs, exit-anywhere; rework leaderboard + add game history

- Widow: preserve card selection across re-renders (no more deselecting)
- Play: reject a second card during trick resolution (fixes hand-count desync)
- Leave: exit available during bidding/widow/trump; a mid-game leave hands the
  seat to AI so the game continues; rooms with no humans are torn down
- Leaderboard: one-time flush + schema migration, win rate as the primary
  ranking metric, per-team shelem and per-seat bid tracking, avg score + bids won
- History: per-game round-by-round records persisted to history.json, a history
  screen, and a vertical round breakdown (with totals) shown to all players at
  hand/game end; result held for 15s

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/index.html

@@ -261,6 +261,7 @@
       </div>
     </div>
     <p id="bid-waiting-msg" class="hint" style="min-height:20px"></p>
+    <button class="overlay-leave-btn" data-overlay-leave>🚪 Leave game</button>
   </div>
 </div>
 
@@ -276,6 +277,7 @@
     </div>
     <button id="btn-confirm-discard" class="btn-primary" disabled>Confirm Discard</button>
     <p id="widow-waiting" class="hint" style="min-height:18px"></p>
+    <button class="overlay-leave-btn" data-overlay-leave>🚪 Leave game</button>
   </div>
 </div>
 
@@ -296,6 +298,7 @@
       <div class="result-icon" style="font-size:2rem">⏳</div>
       <p id="trump-waiting-msg" class="hint"></p>
     </div>
+    <button class="overlay-leave-btn" data-overlay-leave>🚪 Leave game</button>
   </div>
 </div>
 
@@ -306,6 +309,7 @@
     <h3 id="hand-result-title"></h3>
     <p  id="hand-result-detail"></p>
     <div id="hand-result-scores" class="result-scores"></div>
+    <div id="hand-round-breakdown" class="round-breakdown-wrap"></div>
     <p class="hint">Next hand starting…</p>
   </div>
 </div>
@@ -316,6 +320,7 @@
     <div class="result-icon big">🏆</div>
     <h2 id="gameover-title"></h2>
     <div id="gameover-scores" class="gameover-scores"></div>
+    <div id="gameover-breakdown" class="round-breakdown-wrap"></div>
     <button id="btn-new-game" class="btn-primary">New Game</button>
   </div>
 </div>
@@ -367,21 +372,33 @@
       <h2 id="profile-username" class="profile-name"></h2>
       <div class="stat-grid">
         <div class="stat-card">
-          <span class="stat-num" id="stat-games-played">—</span>
-          <span class="stat-label">Games Played</span>
+          <span class="stat-num" id="stat-win-rate">—</span>
+          <span class="stat-label">Win Rate</span>
         </div>
         <div class="stat-card">
           <span class="stat-num" id="stat-games-won">—</span>
           <span class="stat-label">Games Won</span>
         </div>
+        <div class="stat-card">
+          <span class="stat-num" id="stat-games-played">—</span>
+          <span class="stat-label">Games Played</span>
+        </div>
         <div class="stat-card">
           <span class="stat-num" id="stat-shelem">—</span>
           <span class="stat-label">Shelems 🃏</span>
         </div>
         <div class="stat-card">
-          <span class="stat-num" id="stat-total-score">—</span>
-          <span class="stat-label">Total Score</span>
+          <span class="stat-num" id="stat-bids-won">—</span>
+          <span class="stat-label">Bids Won</span>
         </div>
+        <div class="stat-card">
+          <span class="stat-num" id="stat-avg-score">—</span>
+          <span class="stat-label">Avg Score</span>
+        </div>
+      </div>
+
+      <div class="profile-section">
+        <button id="btn-show-history" class="btn-secondary" style="width:100%">📜 Game History</button>
       </div>
 
       <div class="points-legend">
@@ -434,7 +451,7 @@
       <table class="lb-table">
         <thead>
           <tr>
-            <th>#</th><th>Player</th><th>Avg Score</th><th>W</th><th>Played</th><th>🃏</th>
+            <th>#</th><th>Player</th><th>Win %</th><th>W</th><th>P</th><th>Avg</th><th title="Bids won">Bid</th><th title="Shelems">🃏</th>
           </tr>
         </thead>
         <tbody id="lb-body"></tbody>
@@ -443,6 +460,26 @@
   </div>
 </div>
 
+<!-- ══════════════ GAME HISTORY ══════════════ -->
+<div id="screen-history" class="screen">
+  <div class="profile-wrap">
+    <div class="profile-box" style="max-width:560px">
+      <button id="btn-history-back" class="btn-back">← Back</button>
+      <div class="profile-avatar">📜</div>
+      <h2 id="history-title" class="profile-name">Game History</h2>
+      <!-- List of past games -->
+      <div id="history-list" class="history-list"><p class="hint">Loading…</p></div>
+      <!-- Detail of a selected game -->
+      <div id="history-detail" class="hidden">
+        <button id="btn-history-detail-back" class="btn-back" style="position:static;margin-bottom:8px">← All games</button>
+        <h3 id="history-detail-title"></h3>
+        <div id="history-detail-scores" class="gameover-scores"></div>
+        <div id="history-detail-breakdown" class="round-breakdown-wrap"></div>
+      </div>
+    </div>
+  </div>
+</div>
+
 <!-- ══════════════ EXIT CONFIRM ══════════════ -->
 <div id="overlay-exit-confirm" class="overlay hidden">
   <div class="overlay-box small" style="text-align:center">