fix(i18n): remove orphaned merge conflict markers from message files

All three message files had a bare `<<<<<<< HEAD` at line 814 with no
corresponding separator or closing marker, making them invalid JSON and
breaking the Paraglide build.

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

frontend/messages/de.json

@@ -810,7 +810,6 @@
 	"pagination_next": "Weiter",
 	"pagination_page_of": "Seite {page} von {total}",
 	"pagination_nav_label": "Seitennavigation",
-<<<<<<< HEAD
 
 	"common_opens_new_tab": "(öffnet in neuem Tab)",
 

frontend/messages/en.json

@@ -810,7 +810,6 @@
 	"pagination_next": "Next",
 	"pagination_page_of": "Page {page} of {total}",
 	"pagination_nav_label": "Pagination",
-<<<<<<< HEAD
 
 	"common_opens_new_tab": "(opens in new tab)",
 

frontend/messages/es.json

@@ -810,7 +810,6 @@
 	"pagination_next": "Siguiente",
 	"pagination_page_of": "Página {page} de {total}",
 	"pagination_nav_label": "Paginación",
-<<<<<<< HEAD
 
 	"common_opens_new_tab": "(abre en pestaña nueva)",