Initial client scaffold

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

config/konkrete/locals/de_de.local

@@ -0,0 +1,16 @@
+general.width = Breite
+general.height = Höhe
+general.on = An
+general.off = Aus
+
+popup.done = Fertig
+
+popup.yesno.confirm = Bestätigen
+popup.yesno.cancel = Abbrechen
+
+popup.notification.accept = Akzeptieren
+
+popup.choosefile.back = ZURÜCK
+popup.choosefile.title = Datei wählen
+popup.choosefile.choose = Wählen
+popup.choosefile.supported = Unterstützte Dateitypen: