Add detailed logging for Firebase upload debugging

🔍 Upload Debugging:
- Added logs to show when items are added to Hive
- Shows item key and householdId after Hive save
- Logs upload attempts to Firebase
- Shows success/failure for each upload
- Logs reason for skipping Firebase sync

📝 Log Messages:
- 📝 Added item to Hive: {name}, key={key}, householdId={id}
- 🚀 Uploading item to Firebase: {name} (key: {key})
- ✅ Successfully uploaded to Firebase
- ❌ Failed to sync item to Firebase: {error}
- ⚠️ Skipping Firebase sync: householdId={id}, key={key}

🎯 Next Steps for User:
1. Install new APK
2. Add an item while in household
3. Check logcat for upload messages
4. If seeing "⚠️ Skipping" → item.householdId is null
5. If seeing "❌ Failed" → Firebase error details shown
6. If seeing "✅ Successfully" → check Firebase Console

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

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

lib/features/inventory/repositories/inventory_repository_impl.dart

@@ -50,17 +50,23 @@ class InventoryRepositoryImpl implements InventoryRepository {
     item.lastModified = DateTime.now();
     await box.add(item);
 
+    print('📝 Added item to Hive: ${item.name}, key=${item.key}, householdId=${item.householdId}');
+
     // Sync to Firebase if in a household
     if (item.householdId != null && item.key != null) {
+      print('🚀 Uploading item to Firebase: ${item.name} (key: ${item.key})');
       try {
         await _firebaseService.addFoodItem(
           item.householdId!,
           item,
           item.key.toString(),
         );
+        print('✅ Successfully uploaded to Firebase');
       } catch (e) {
-        print('Failed to sync item to Firebase: $e');
+        print('❌ Failed to sync item to Firebase: $e');
       }
+    } else {
+      print('⚠️ Skipping Firebase sync: householdId=${item.householdId}, key=${item.key}');
     }
   }