feat: keep qty=0 instead of auto-delete, ask user to confirm via banner

- useFromInventory: replace DELETE with UPDATE qty=0 when stock hits 0
  (both normal path and use-all-locations path)
- listInventory: add WHERE quantity > 0 so qty=0 rows are invisible in
  the regular inventory list
- New API actions: inventory_finished_items (query) and
  inventory_confirm_finished (delete after user confirms)
- Banner: new 'finished' type (priority 600, above anomalies)
  Shows: '{name} — è finito?' with two buttons
  'Sì, è finito' → permanently deletes the qty=0 row
  'No, ne ho ancora' → navigates to add-inventory form
- i18n: banner_finished_* and toast.product_finished_confirmed (it/en/de)
- DB migration: restored 75 auto-deleted products (last 30 days) as
  qty=0 inventory rows so they appear in the banner queue

translations/de.json

@@ -105,7 +105,11 @@
         "banner_expiring_today": "Läuft heute ab!",
         "banner_expiring_tomorrow": "Läuft morgen ab",
         "banner_expiring_days": "Läuft in {days} Tagen ab",
-        "banner_expiring_action_use": "Jetzt verwenden"
+        "banner_expiring_action_use": "Jetzt verwenden",
+        "banner_finished_title": "aufgebraucht?",
+        "banner_finished_detail": "Ich habe vermerkt, dass {name} auf null gesunken ist. Ist es wirklich leer, oder hast du noch welches?",
+        "banner_finished_action_yes": "Ja, aufgebraucht",
+        "banner_finished_action_no": "Nein, ich habe noch welches"
     },
     "inventory": {
         "title": "Vorrat",
@@ -426,6 +430,7 @@
         "finished_to_bring": "🛒 Produkt aufgebraucht → zu Bring! hinzugefügt",
         "thrown_away": "🗑️ {name} weggeworfen!",
         "thrown_away_partial": "🗑️ {qty} {unit} von {name} weggeworfen",
+        "product_finished_confirmed": "✅ Entfernt — wieder hinzufügen, wenn du nachkaufst",
         "appliance_added": "Gerät hinzugefügt",
         "item_added": "{name} hinzugefügt"
     },

translations/en.json

@@ -105,7 +105,11 @@
         "banner_expiring_today": "Expires today!",
         "banner_expiring_tomorrow": "Expires tomorrow",
         "banner_expiring_days": "Expires in {days} days",
-        "banner_expiring_action_use": "Use now"
+        "banner_expiring_action_use": "Use now",
+        "banner_finished_title": "finished?",
+        "banner_finished_detail": "I recorded that {name} reached zero stock. Is it really gone, or do you still have some?",
+        "banner_finished_action_yes": "Yes, it's done",
+        "banner_finished_action_no": "No, I still have some"
     },
     "inventory": {
         "title": "Pantry",
@@ -426,6 +430,7 @@
         "finished_to_bring": "🛒 Product finished → added to Bring!",
         "thrown_away": "🗑️ {name} thrown away!",
         "thrown_away_partial": "🗑️ Thrown away {qty} {unit} of {name}",
+        "product_finished_confirmed": "✅ Removed — add it again when you restock",
         "appliance_added": "Appliance added",
         "item_added": "{name} added"
     },

translations/it.json

@@ -105,7 +105,11 @@
         "banner_expiring_today": "Scade oggi!",
         "banner_expiring_tomorrow": "Scade domani",
         "banner_expiring_days": "Scade tra {days} giorni",
-        "banner_expiring_action_use": "Usa ora"
+        "banner_expiring_action_use": "Usa ora",
+        "banner_finished_title": "è finito?",
+        "banner_finished_detail": "Ho registrato che {name} ha toccato quota zero. È davvero finito o hai ancora delle scorte?",
+        "banner_finished_action_yes": "Sì, è finito",
+        "banner_finished_action_no": "No, ne ho ancora"
     },
     "inventory": {
         "title": "Dispensa",
@@ -426,6 +430,7 @@
         "finished_to_bring": "🛒 Prodotto finito → aggiunto a Bring!",
         "thrown_away": "🗑️ {name} buttato!",
         "thrown_away_partial": "🗑️ Buttato {qty} {unit} di {name}",
+        "product_finished_confirmed": "✅ Rimosso — riaggiungi quando ne ricompri",
         "appliance_added": "Elettrodomestico aggiunto",
         "item_added": "{name} aggiunto"
     },