Discard items left in their pickup box past a 15-minute window

An item's pickup window starts when it goes into its box. Once it runs
out, the item is discarded without a refund and the box is freed; a box
that's open at that moment is left alone. With no scheduler yet, reads,
box actions and the kitchen simulation check for expired items first.

The order card shows a live countdown under "Ready for pickup" and a
"Not picked up in time" banner once discarded. Also bounces the lock
icon and animates the pickup button's label changes.

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

tests/format.test.ts

@@ -1,6 +1,11 @@
 import { describe, expect, it } from 'vitest'
 
-import { formatDuration, formatEtaClock, formatEtaParts } from '#/lib/format.ts'
+import {
+  formatCountdown,
+  formatDuration,
+  formatEtaClock,
+  formatEtaParts,
+} from '#/lib/format.ts'
 
 describe('formatDuration', () => {
   it('rounds up to at least 1 minute', () => {
@@ -64,3 +69,15 @@ describe('formatEtaParts', () => {
     })
   })
 })
+
+describe('formatCountdown', () => {
+  it('shows minutes and zero-padded seconds, rounding up', () => {
+    expect(formatCountdown(15 * 60 * 1000)).toBe('15:00')
+    expect(formatCountdown(65_500)).toBe('1:06')
+    expect(formatCountdown(9_000)).toBe('0:09')
+  })
+
+  it('stops at zero once the time is up', () => {
+    expect(formatCountdown(-5_000)).toBe('0:00')
+  })
+})