Content page about the "life clock" concept, ending with an internal
link to /7-tage-klarheits-check. Styled by hand (headings/quote match
RichText.tsx's converter output) since it's not CMS-backed content.
Renames the route, its canonical/OG metadata, Navbar's active-route
list, and the testimonials page filter to match. Also updates CTA
copy ("Klarheits-Check starten"), the "So funktioniert" heading, the
"3. Umsetzen" step text, and the breadcrumb label.
Marco