feat: aggiungi pulsante svuota piano settimanale

- Sposta .btn-clear da ShoppingList.vue (scoped) a style.css (globale)
- Aggiunge hasMeals, clearAll e btn-clear in MealPlanner.vue
- Aggiunge 4 test di integrazione per il nuovo pulsante

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

src/pages/MealPlanner.vue

@@ -22,6 +22,8 @@
       Genera lista della spesa
     </button>
 
+    <button v-if="hasMeals" class="btn-clear" @click="clearAll">Svuota piano</button>
+
     <div class="btn-share-row">
       <button class="btn-share" @click="openShare">
         <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
@@ -99,7 +101,7 @@
 </template>
 
 <script setup>
-import { reactive, watch, ref, onUnmounted, nextTick } from 'vue'
+import { reactive, watch, ref, computed, onUnmounted, nextTick } from 'vue'
 import MealCard from '../components/MealCard.vue'
 import { save, load } from '../utils/storage.js'
 import QRCode from 'qrcode'
@@ -137,6 +139,14 @@ function removeItem(day, slot, idx) {
   meals[day][slot].splice(idx, 1)
 }
 
+const hasMeals = computed(() =>
+  days.some(d => ['colazione', 'pranzo', 'cena'].some(s => meals[d.id][s].length > 0))
+)
+
+function clearAll() {
+  if (confirm('Svuotare tutto il piano settimanale?')) Object.assign(meals, defaultMeals())
+}
+
 function generateShopping() {
   const allItems = days.flatMap(d =>
     ['colazione', 'pranzo', 'cena'].flatMap(slot => meals[d.id][slot])

src/pages/ShoppingList.vue

@@ -144,21 +144,6 @@ function clearAll() {
   background: var(--color-border);
 }
 
-/* bottone distruttivo in ghost style — meno aggressivo del solid rosso */
-.btn-clear {
-  width: 100%;
-  background: transparent;
-  color: var(--color-danger);
-  border: 1.5px solid var(--color-danger);
-  margin-top: 16px;
-  font-weight: 600;
-}
-
-.btn-clear:active {
-  background: var(--color-danger-muted);
-  opacity: 1;
-}
-
 .empty-state {
   display: flex;
   flex-direction: column;

src/style.css

@@ -78,6 +78,21 @@ button {
 
 button:active { opacity: 0.75; }
 
+/* bottone distruttivo in ghost style — meno aggressivo del solid rosso */
+.btn-clear {
+  width: 100%;
+  background: transparent;
+  color: var(--color-danger);
+  border: 1.5px solid var(--color-danger);
+  margin-top: 16px;
+  font-weight: 600;
+}
+
+.btn-clear:active {
+  background: var(--color-danger-muted);
+  opacity: 1;
+}
+
 input[type="text"],
 input[type="number"] {
   font-size: 1rem;

tests/integration/MealPlanner.test.js

@@ -1,4 +1,4 @@
-import { describe, it, expect } from 'vitest'
+import { describe, it, expect, vi } from 'vitest'
 import { mount } from '@vue/test-utils'
 import { nextTick } from 'vue'
 import MealPlanner from '../../src/pages/MealPlanner.vue'
@@ -150,3 +150,41 @@ describe('MealPlanner — genera lista della spesa', () => {
     expect(load('shopping', [])).toHaveLength(0)
   })
 })
+
+describe('MealPlanner — svuota piano', () => {
+  it('non mostra il pulsante se il piano è vuoto', () => {
+    const w = mountPlanner()
+    expect(w.find('.btn-clear').exists()).toBe(false)
+  })
+
+  it('mostra il pulsante se c\'è almeno un pasto', () => {
+    seedMeals({ lunedi: { colazione: ['caffè'], pranzo: [], cena: [] } })
+    const w = mountPlanner()
+    expect(w.find('.btn-clear').exists()).toBe(true)
+  })
+
+  it('svuota il piano dopo conferma', async () => {
+    vi.spyOn(window, 'confirm').mockReturnValue(true)
+    seedMeals({ lunedi: { colazione: ['caffè'], pranzo: ['pasta'], cena: [] } })
+    const w = mountPlanner()
+
+    await w.find('.btn-clear').trigger('click')
+    await nextTick()
+
+    const saved = load('meals', {})
+    expect(saved.lunedi.colazione).toHaveLength(0)
+    expect(saved.lunedi.pranzo).toHaveLength(0)
+    expect(w.find('.btn-clear').exists()).toBe(false)
+  })
+
+  it('non svuota se l\'utente annulla', async () => {
+    vi.spyOn(window, 'confirm').mockReturnValue(false)
+    seedMeals({ lunedi: { colazione: ['caffè'], pranzo: [], cena: [] } })
+    const w = mountPlanner()
+
+    await w.find('.btn-clear').trigger('click')
+    await nextTick()
+
+    expect(load('meals', {}).lunedi.colazione).toHaveLength(1)
+  })
+})