feat: implement cart icon component with quantity badge and integrate into store header for improved UI

src/app/shared/components/cart-icon/cart-icon.component.scss

@@ -0,0 +1,79 @@
+:host {
+  display: inline-block;
+  vertical-align: middle;
+}
+
+.cart-icon {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  background: transparent;
+  border: none;
+  padding: 4px;
+  margin: 0;
+  color: #666666;
+  cursor: pointer;
+  outline: none;
+  transition: color 0.15s ease-in-out, transform 0.1s ease-in-out;
+  border-radius: 4px;
+
+  // Active state subtle scale down
+  &:active:not(:disabled) {
+    transform: scale(0.92);
+  }
+
+  // Focus ring for accessibility
+  &:focus-visible {
+    outline: 2px solid var(--tenant-primary);
+    outline-offset: 2px;
+  }
+
+  // Disabled state
+  &:disabled {
+    color: #A0A0A0;
+    cursor: not-allowed;
+    pointer-events: none;
+  }
+}
+
+// Hover/Active/Focus colors (non-disabled)
+.cart-icon:hover:not(:disabled),
+.cart-icon:focus-visible:not(:disabled),
+.cart-icon.hover-preview:not(:disabled),
+:host(.hover-preview) .cart-icon:not(:disabled) {
+  color: var(--tenant-primary);
+}
+
+.cart-icon__container {
+  position: relative;
+  display: inline-flex;
+}
+
+.cart-icon__glyph {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 23px;
+  height: 23px;
+  font-size: 23px;
+  line-height: 1;
+}
+
+.cart-icon__badge {
+  position: absolute;
+  top: -8px;
+  right: -8px;
+  min-width: 18px;
+  height: 18px;
+  border-radius: 9px;
+  background-color: var(--tenant-primary);
+  color: #ffffff;
+  font-size: 10px;
+  font-weight: 700;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0 4px;
+  line-height: 1;
+  box-sizing: border-box;
+}