aggiungi generazione lista spesa dal piano pasti

Bottone "Genera lista della spesa" in fondo alla pagina Piano Pasti:
- raccoglie tutti gli item da tutti i giorni e pasti
- deduplica (case-insensitive) e salta item già presenti in lista
- aggiunge come non spuntati alla lista esistente
- naviga automaticamente alla tab Lista della spesa

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/App.vue

@@ -1,6 +1,6 @@
 <template>
   <div id="app-root">
-    <MealPlanner v-if="page === 'meal'" />
+    <MealPlanner v-if="page === 'meal'" @go-shop="page = 'shop'" />
     <Converter   v-else-if="page === 'convert'" />
     <ShoppingList v-else-if="page === 'shop'" />
     <BottomNav v-model="page" />

src/pages/MealPlanner.vue

@@ -13,6 +13,14 @@
       @add="(slot, text) => addItem(day.id, slot, text)"
       @remove="(slot, idx) => removeItem(day.id, slot, idx)"
     />
+    <button class="btn-generate" @click="generateShopping">
+      <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+        <path d="M6 2L3 6v14a2 2 0 002 2h14a2 2 0 002-2V6l-3-4z"/>
+        <line x1="3" y1="6" x2="21" y2="6"/>
+        <path d="M16 10a4 4 0 01-8 0"/>
+      </svg>
+      Genera lista della spesa
+    </button>
   </div>
 </template>
 
@@ -21,6 +29,8 @@ import { reactive, watch } from 'vue'
 import MealCard from '../components/MealCard.vue'
 import { save, load } from '../utils/storage.js'
 
+const emit = defineEmits(['go-shop'])
+
 const days = [
   { id: 'lunedi',    label: 'Lunedì'    },
   { id: 'martedi',   label: 'Martedì'   },
@@ -50,4 +60,44 @@ function addItem(day, slot, text) {
 function removeItem(day, slot, idx) {
   meals[day][slot].splice(idx, 1)
 }
+
+function generateShopping() {
+  const allItems = days.flatMap(d =>
+    ['colazione', 'pranzo', 'cena'].flatMap(slot => meals[d.id][slot])
+  )
+  const existing = load('shopping', [])
+  const existingNames = new Set(existing.map(i => i.name.toLowerCase()))
+  const seen = new Set()
+  const toAdd = []
+  for (const name of allItems) {
+    const key = name.toLowerCase()
+    if (!existingNames.has(key) && !seen.has(key)) {
+      seen.add(key)
+      toAdd.push({ id: Date.now() + Math.random(), name, checked: false })
+    }
+  }
+  save('shopping', [...existing, ...toAdd])
+  emit('go-shop')
+}
 </script>
+
+<style scoped>
+.btn-generate {
+  width: 100%;
+  margin-top: 8px;
+  background: var(--color-primary);
+  color: #fff;
+  font-weight: 600;
+  font-size: 0.95rem;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  min-height: 48px;
+  border-radius: var(--radius);
+}
+
+.btn-generate:active {
+  opacity: 0.85;
+}
+</style>