fix(ui): restore dictionary card styles and clean up activity heatmap labels

app/static/index.html

@@ -71,7 +71,7 @@
                     <span class="trainer-text">Тренажёр SRS</span>
                     <span id="srs-badge" class="srs-due-badge">0</span>
                 </button>
-                <button id="stats-open-btn" class="btn btn-outline btn-sm stat-open-btn" title="Активность (GitHub Heatmap) и аналитика">
+                <button id="stats-open-btn" class="btn btn-outline btn-sm stat-open-btn" title="Календарь активности и статистика">
                     <span>📊 Статистика</span>
                 </button>
                 <button id="export-open-btn" class="btn btn-outline btn-sm" title="Экспорт словаря">
@@ -569,10 +569,10 @@
                     </div>
                 </div>
 
-                <!-- GitHub-Style Contribution Heatmap -->
+                <!-- Contribution Activity Heatmap -->
                 <div class="heatmap-section">
                     <div class="heatmap-header">
-                        <h4>🟩 Календарь активности (GitHub-style Heatmap)</h4>
+                        <h4>🟩 Календарь активности</h4>
                         <div class="heatmap-legend">
                             <span>Меньше</span>
                             <span class="legend-cell lvl-0" title="0 повторений"></span>