Add shipping cost management and checkout shipping fees.

Business store shipping groups/static rates UI, and customer checkout that quotes and applies shipping on delivery and payment.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/customer/src/components/checkout/CheckoutStepper.module.css

@@ -1,3 +1,4 @@
+/* Horizontal top stepper */
 .stepper {
   display: flex;
   align-items: flex-end;
@@ -94,3 +95,91 @@
     margin: 0 4px 13px;
   }
 }
+
+/* Tall side panel — current step only */
+.rail {
+  display: flex;
+  flex-direction: column;
+  align-items: stretch;
+  width: 112px;
+  flex-shrink: 0;
+  min-height: 320px;
+  align-self: stretch;
+  padding: 18px 12px;
+  background: var(--glass-bg);
+  backdrop-filter: blur(24px);
+  -webkit-backdrop-filter: blur(24px);
+  border: 1px solid var(--glass-border);
+  border-radius: var(--radius);
+  box-shadow: var(--glass-shadow);
+  font-family: inherit;
+}
+
+.railCurrent {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 12px;
+  text-align: center;
+  min-height: 160px;
+}
+
+.railIconWrap {
+  width: 52px;
+  height: 52px;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  border-radius: 14px;
+  color: var(--primary);
+  background: rgba(var(--primary-rgb) / 0.14);
+  border: 1px solid rgba(var(--primary-rgb) / 0.28);
+}
+
+.railTitle {
+  font-size: 13px;
+  font-weight: 700;
+  color: var(--text-primary);
+  line-height: 1.35;
+}
+
+.railIndex {
+  font-size: 11px;
+  font-weight: 500;
+  color: var(--text-muted);
+}
+
+@media (max-width: 760px) {
+  .rail {
+    width: 100%;
+    min-height: 0;
+    flex-direction: row;
+    align-items: center;
+    justify-content: center;
+    gap: 12px;
+    padding: 14px 16px;
+  }
+
+  .railCurrent {
+    flex: 0 0 auto;
+    min-height: 0;
+    flex-direction: row;
+    gap: 10px;
+  }
+
+  .railIconWrap {
+    width: 44px;
+    height: 44px;
+    border-radius: 12px;
+  }
+
+  .railTitle {
+    font-size: 14px;
+  }
+
+  .railIndex {
+    display: none;
+  }
+}