fix(locale): align all English MDX page links and add automated links validation test to prevent language drift

content/en/ueber-uns.mdx

@@ -11,7 +11,7 @@ layout: "fullBleed"
   description="Since 2015, we have been growing continuously to meet the demands of the energy transition and digitalization. As a corporate group, we pool specialized expertise under one roof."
   videoUrl="/assets/videos/web/hero-bahnkreuzung.mp4"
   linkText="Open Positions"
-  linkHref="/en/karriere"
+  linkHref="/en/career"
   secondaryCtaLabel="Discover Company"
   secondaryCtaHref="#structure"
 />
@@ -128,5 +128,5 @@ layout: "fullBleed"
   title="Ready for Your Project?"
   description="We are always looking for new challenges and strong partners. Contact us for a non-binding consultation on your project."
   ctaLabel="Contact Us Now"
-  ctaHref="/en/kontakt"
+  ctaHref="/en/contact"
 />