feat: Add Pause system, User Profile Dashboard, and shift grid with neighbour fence

- Implement in-game pause with Space/KeyP hotkeys and pause banner overlay
- Split Auth modal into clean Profile Dashboard (stats, coins, cloud save status) and Guest Login
- Shift lawn startY to 108 to make top-row zombie HP bars 100% visible
- Render decorative wooden neighbour fence above top row

game/css/style.css

@@ -450,10 +450,98 @@ canvas#gameCanvas {
   cursor: not-allowed;
 }
 
-/* Auth Modal Styles */
+/* Auth Modal & Profile Dashboard Styles */
 .auth-card {
-  max-width: 420px;
-  width: 90%;
+  max-width: 440px;
+  width: 92%;
+}
+
+.auth-view.hidden {
+  display: none;
+}
+
+.profile-header-card {
+  display: flex;
+  align-items: center;
+  gap: 14px;
+  background: rgba(0, 0, 0, 0.4);
+  border: 1.5px solid #81c784;
+  border-radius: 10px;
+  padding: 10px 14px;
+  margin-bottom: 12px;
+}
+
+.profile-avatar-icon {
+  font-size: 32px;
+  background: rgba(255, 255, 255, 0.1);
+  width: 50px;
+  height: 50px;
+  border-radius: 50%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  border: 2px solid #81c784;
+}
+
+.profile-info-text {
+  text-align: left;
+}
+
+.profile-username {
+  font-size: 18px;
+  font-weight: bold;
+  color: #ffeb3b;
+}
+
+.profile-status-badge {
+  font-size: 11px;
+  color: #a5d6a7;
+  margin-top: 2px;
+}
+
+.profile-stats-grid {
+  display: grid;
+  grid-template-columns: repeat(2, 1fr);
+  gap: 8px;
+  margin-bottom: 8px;
+}
+
+.profile-stat-box {
+  background: rgba(0, 0, 0, 0.35);
+  border: 1px solid #5d4037;
+  border-radius: 8px;
+  padding: 8px 10px;
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+}
+
+.profile-stat-box .stat-label {
+  font-size: 11px;
+  color: #bcaaa4;
+}
+
+.profile-stat-box .stat-value {
+  font-size: 15px;
+  font-weight: bold;
+  color: #fff;
+  margin-top: 2px;
+}
+
+.btn-pause {
+  background: #37474f;
+  color: #eceff1;
+  border-color: #78909c;
+}
+.btn-pause:hover {
+  background: #455a64;
+  border-color: #b0bec5;
+}
+.btn-pause.active {
+  background: #d84315 !important;
+  border-color: #ffab91 !important;
+  color: #fff !important;
+  box-shadow: 0 0 10px rgba(255, 87, 34, 0.6) !important;
 }
 
 .auth-input {