Collect ready items from pickup boxes instead of "I picked this up"

A ready Order Item now gets the lowest-numbered free Pickup Box (or waits
for one to free up), shown as "Pickup box N" on its status. The customer
opens the box from their order and closes it again; closing marks the
item picked up and hands the box to the next waiting item.

On the order card the box button comes first, full width on mobile, with
a padlock that lifts on open and snaps shut before the button collapses
away.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/components/orders/OrderStatusView.module.scss

@@ -299,6 +299,26 @@
     }
   }
 
+  .pickupButton {
+    overflow: hidden;
+    white-space: nowrap;
+    border-color: $color-text;
+    background: $color-text;
+    color: $color-background;
+    font-weight: 600;
+
+    &:hover:not(:disabled) {
+      border-color: $color-text;
+      opacity: 0.9;
+    }
+
+    @media (max-width: $breakpoint-tablet) {
+      flex-basis: 100%;
+      justify-content: center;
+      margin-bottom: $space-2;
+    }
+  }
+
   .actionIcon {
     width: 1rem;
     height: 1rem;