Fix invisible Stripe pay button, add brand favicon/OG image, navbar 3x3-System CTA, blog hero crop

- PaymentStep: bg-brand-primary was never a real Tailwind class, leaving
  the "Jetzt bezahlen" button unstyled/invisible; switched to bg-brand
  with dark text, matching every other CTA on the site.
- New app/icon.svg + app/apple-icon.png + app/favicon.ico: brand-yellow
  rounded square with a bold italic "e", replacing the Next.js default.
- New public/og-image.png (logo on the site's cream background) wired in
  as the SEO fallback default OG image/description/title in payload.ts.
- Navbar CTA: "Klarheitskompass" -> "Mein 3x3-System", now links to
  /3x3-system (page not built yet).
- Blog overview hero image anchored to the top instead of center-cropped.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/blog/page.tsx

@@ -43,7 +43,7 @@ export default async function BlogOverviewPage() {
             </p>
           </div>
           <div className="relative w-full sm:absolute sm:inset-y-0 sm:right-0 sm:w-[68%] h-56 sm:h-full">
-            <Image alt="" src="/hero.png" fill sizes="(min-width: 640px) 68vw, 100vw" className="object-cover" />
+            <Image alt="" src="/hero.png" fill sizes="(min-width: 640px) 68vw, 100vw" className="object-cover object-top" />
             <div className="hidden sm:block absolute inset-y-0 left-0 w-72 bg-gradient-to-r from-bg-base to-transparent" />
             <div className="absolute inset-x-0 bottom-0 h-16 bg-gradient-to-t from-bg-base to-transparent" />
           </div>

app/checkout/components/PaymentStep.tsx

@@ -80,7 +80,7 @@ function StripePaymentForm({ orderNumber }: { orderNumber: string }) {
       <button
         type="submit"
         disabled={!stripe || submitting}
-        className="rounded-full bg-brand-primary px-6 py-3 text-white font-semibold disabled:opacity-50"
+        className="rounded-full bg-brand px-6 py-3 text-text-primary font-semibold hover:bg-brand-hover active:scale-[0.97] transition-all disabled:opacity-50"
       >
         {submitting ? "Wird bearbeitet…" : "Jetzt bezahlen"}
       </button>

app/components/Navbar.tsx

@@ -519,10 +519,10 @@ export function Navbar({ singleActiveProduct }: { singleActiveProduct: boolean }
                 Newsletter
               </button>
               <Link
-                href="/lebensuhr"
+                href="/3x3-system"
                 className="px-6 py-4 rounded-sm bg-brand text-h4 font-bold text-text-primary whitespace-nowrap hover:bg-brand-hover active:scale-[0.97] transition-all"
               >
-                Klarheitskompass
+                Mein 3x3-System
               </Link>
             </div>
 
@@ -668,11 +668,11 @@ export function Navbar({ singleActiveProduct }: { singleActiveProduct: boolean }
                   Newsletter
                 </button>
                 <Link
-                  href="/lebensuhr"
+                  href="/3x3-system"
                   onClick={closeMobile}
                   className="md:hidden min-h-11 flex items-center justify-center px-6 py-4 rounded-sm bg-brand text-h4 font-bold text-text-primary hover:bg-brand-hover active:scale-[0.97] transition-all"
                 >
-                  Klarheitskompass
+                  Mein 3x3-System
                 </Link>
               </motion.div>
             </div>

app/icon.svg

@@ -0,0 +1,13 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" width="64" height="64">
+  <rect x="0" y="0" width="64" height="64" rx="14" fill="#f6a701" />
+  <text
+    x="32"
+    y="46"
+    text-anchor="middle"
+    font-family="Georgia, 'Playfair Display', 'Times New Roman', serif"
+    font-weight="700"
+    font-style="italic"
+    font-size="42"
+    fill="#1a1a1a"
+  >e</text>
+</svg>

app/lib/payload.ts

@@ -964,10 +964,11 @@ export type SeoSettings = {
 // filling in the CompanySettings SEO tab is optional, not a hard
 // dependency for the site to render sensible metadata.
 const SEO_SETTINGS_FALLBACK: SeoSettings = {
-  defaultTitle: "einfach produktiv. – Werkzeuge und Impulse für einen leichteren Alltag",
+  defaultTitle: "einfach produktiv. – Weil du auch noch ein Leben hast",
   titleTemplate: "%s | einfach produktiv.",
-  defaultDescription: "Werkzeuge, Impulse und ein Blog für mehr Klarheit im Alltag.",
-  defaultOgImage: null,
+  defaultDescription:
+    "Kleine Impulse, praktische Werkzeuge und ehrliche Gedanken für mehr Klarheit im Alltag – weil du auch noch ein Leben hast.",
+  defaultOgImage: "/og-image.png",
 };
 
 // Same ISR-cached, public-catalog-freshness fetch as getKleinunternehmer()