Browser session recovery, price tracking, and dashboard improvements

- Add browser session validation and auto-restart for BestBuy/GameStop scrapers
- Add price change detection and notifications
- Remove PokemonCenter scraper (now uses Chrome Extension)
- Dashboard UI improvements

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

dashboard/static/style.css

@@ -1103,6 +1103,57 @@ h3 {
   grid-column: span 2;
 }
 
+/* Chrome Extension Card */
+.extension-card {
+  grid-column: span 2;
+  border-color: #ffcb05;
+}
+
+.extension-badge {
+  padding: 4px 12px;
+  border-radius: 12px;
+  font-size: 12px;
+  font-weight: 600;
+}
+
+.extension-badge.connected {
+  background: rgba(0, 255, 0, 0.2);
+  color: #00ff00;
+}
+
+.extension-badge.disconnected {
+  background: rgba(255, 100, 100, 0.2);
+  color: #ff6464;
+}
+
+.extension-stats {
+  display: grid;
+  grid-template-columns: repeat(3, 1fr);
+  gap: 15px;
+  margin-top: 10px;
+}
+
+.extension-stat {
+  background: var(--bg-primary);
+  padding: 12px;
+  border-radius: 8px;
+  text-align: center;
+}
+
+.extension-stat .stat-label {
+  display: block;
+  font-size: 12px;
+  color: var(--text-secondary);
+  margin-bottom: 5px;
+}
+
+.extension-stat .stat-value {
+  display: block;
+  font-size: 18px;
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
 .scrapers-grid {
   display: grid;
   grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));