feat(packing): item quantity, bag rename, multi-user bags, save as template

- Add quantity field to packing items (persisted, visible per item)
- Bags are now renamable (click to edit in sidebar)
- Bags support multiple user assignments with avatar display
- New packing_bag_members table for multi-user bag ownership
- Save current packing list as reusable template
- Add bag members API endpoint (PUT /bags/:bagId/members)
- Migration 74: quantity on packing_items, user_id on packing_bags, packing_bag_members table

client/src/i18n/translations/de.ts

@@ -1106,6 +1106,10 @@ const de: Record<string, string | { name: string; category: string }[]> = {
   'packing.template': 'Vorlage',
   'packing.templateApplied': '{count} Einträge aus Vorlage hinzugefügt',
   'packing.templateError': 'Vorlage konnte nicht angewendet werden',
+  'packing.saveAsTemplate': 'Als Vorlage speichern',
+  'packing.templateName': 'Vorlagenname',
+  'packing.templateSaved': 'Packliste als Vorlage gespeichert',
+  'packing.assignUser': 'Person zuweisen',
   'packing.bags': 'Gepäck',
   'packing.noBag': 'Nicht zugeordnet',
   'packing.totalWeight': 'Gesamtgewicht',