fix(content): correct ISO certificate validity dates from OCR-verified scans

content/en/zertifikate.mdx

@@ -23,21 +23,21 @@ layout: "fullBleed"
       description: 'Environmental Management System',
       pdfUrl: '/assets/certificates/iso14001.pdf',
       type: 'iso',
-      date: '14.12.2023',
+      date: '06.12.2023 – 05.12.2026',
     },
     {
       title: 'ISO 9001:2015',
       description: 'Quality Management System',
       pdfUrl: '/assets/certificates/iso9001.pdf',
       type: 'iso',
-      date: '14.12.2023',
+      date: '06.12.2023 – 05.12.2026',
     },
     {
       title: 'DIN EN ISO 45001:2018',
       description: 'Occupational Health and Safety',
       pdfUrl: '/assets/certificates/iso45001.pdf',
       type: 'iso',
-      date: '05.12.2025',
+      date: '06.12.2025 – 05.12.2028',
     },
     {
       title: 'Commercial Liability Insurance',