Add German translation for 'townhouse' in falukant.json

- Updated the German localization file to include the translation for 'townhouse' as 'Stadthaus'.
- This addition enhances the application's multilingual support and improves user experience for German-speaking users.

frontend/src/i18n/locales/de/falukant.json

@@ -572,7 +572,8 @@
                 "backyard_room": "Hinterhofzimmer",
                 "wooden_house": "Holzhütte",
                 "straw_hut": "Strohhütte",
-                "family_house": "Familienhaus"
+                "family_house": "Familienhaus",
+                "townhouse": "Stadthaus"
             }
         },
         "nobility": {