fix(i18n): remove trailing comma from all three message files

Standard JSON does not allow trailing commas. The comma after the last
key in de/en/es.json caused paraglide to fail compilation, which meant
messages.js was never generated and all component tests crashed on import.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/messages/de.json

@@ -188,5 +188,5 @@
 	"comp_taginput_placeholder_create": "Schlagworte hinzufügen...",
 	"comp_taginput_placeholder_filter": "Nach Schlagworten filtern...",
 	"comp_taginput_remove": "Schlagwort entfernen",
-	"comp_taginput_create_hint": "Enter drücken um Schlagwort zu erstellen.",
+	"comp_taginput_create_hint": "Enter drücken um Schlagwort zu erstellen."
 }