Add household sharing feature

✨ Features:
- Create household with 6-character shareable code
- Join existing household with code
- View household members and owner
- Leave household functionality
- Automatic inventory filtering by household
- Persistent household settings across app updates

🔧 Technical changes:
- Added Household model with Hive adapter (typeId: 4)
- Updated AppSettings with userName and currentHouseholdId fields
- Modified InventoryRepository to filter items by household
- Updated Add Item screen to set householdId on new items
- Added HouseholdScreen with full CRUD operations
- Integrated household sharing into Settings navigation

🎯 Behavior:
- Users not in a household see only their personal items
- Users in a household see shared household items
- New items automatically tagged with current household

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

lib/features/settings/models/app_settings.g.dart

@@ -22,13 +22,15 @@ class AppSettingsAdapter extends TypeAdapter<AppSettings> {
       discordNotificationsEnabled: fields[2] as bool,
       defaultView: fields[3] as String,
       sortBy: fields[4] as String,
+      userName: fields[5] as String?,
+      currentHouseholdId: fields[6] as String?,
     );
   }
 
   @override
   void write(BinaryWriter writer, AppSettings obj) {
     writer
-      ..writeByte(5)
+      ..writeByte(7)
       ..writeByte(0)
       ..write(obj.discordWebhookUrl)
       ..writeByte(1)
@@ -38,7 +40,11 @@ class AppSettingsAdapter extends TypeAdapter<AppSettings> {
       ..writeByte(3)
       ..write(obj.defaultView)
       ..writeByte(4)
-      ..write(obj.sortBy);
+      ..write(obj.sortBy)
+      ..writeByte(5)
+      ..write(obj.userName)
+      ..writeByte(6)
+      ..write(obj.currentHouseholdId);
   }
 
   @override