fix: auto-load shopping list from current meal plan

When navigating to /shopping without a mealPlanId, fetch the current
meal plan first and use its ID to load the shopping list.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/views/ShoppingListView.vue

@@ -96,10 +96,11 @@
 import { ref, computed, onMounted } from 'vue'
 import { useRoute } from 'vue-router'
 import ShoppingItem from '../components/ShoppingItem.vue'
-import { useShoppingStore } from '../stores/mealPlan'
+import { useShoppingStore, useMealPlanStore } from '../stores/mealPlan'
 
 const route = useRoute()
 const store = useShoppingStore()
+const mealPlanStore = useMealPlanStore()
 
 const collapsed = ref<Set<string>>(new Set())
 
@@ -140,8 +141,19 @@ const checked = computed(() => store.items.filter(i => i.isChecked).length)
 const unchecked = computed(() => store.items.filter(i => !i.isChecked).length)
 const progress = computed(() => store.items.length ? Math.round((checked.value / store.items.length) * 100) : 0)
 
-onMounted(() => {
+onMounted(async () => {
   const id = route.params['mealPlanId']
-  store.fetchItems(Array.isArray(id) ? id[0] : id)
+  const mealPlanId = Array.isArray(id) ? id[0] : id
+  if (mealPlanId) {
+    store.fetchItems(mealPlanId)
+  } else {
+    // No mealPlanId in URL — fetch current plan and use its ID
+    if (!mealPlanStore.currentPlan) {
+      await mealPlanStore.fetchCurrentPlan()
+    }
+    if (mealPlanStore.currentPlan?.id) {
+      store.fetchItems(mealPlanStore.currentPlan.id)
+    }
+  }
 })
 </script>