Add ToDo-Karten product page, fluid design tokens, and Navbar/Hero fixes

New /todo-cards page (Hero, How-it-works, Focus, Testimonials, Pricing)
built with the fluid clamp() token system (app/lib/fluid.ts) and
scroll-reveal animations (app/components/Reveal.tsx), matching styling
consistency with /challenge's testimonial section.

Navbar: page-aware active state and anchor-link navigation from any
route (not just "/"), fixed logo click to actually navigate instead of
silently rewriting the URL, fluid nav text size, custom hash-scroll
handling for cross-page anchor links.

Hero: responsive breakpoint fix for the text/image split at Tablet
widths, entrance animation for the brand's orange dot, removed a red
dot artifact from hero.png.

Also includes prior uncommitted work on About/Blog/Newsletter/Footer
and the cart lib (app/lib/cart.ts).

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

app/page.tsx

@@ -1,3 +1,4 @@
+import type { Metadata } from "next";
 import { Hero } from "./components/Hero";
 import { Divider } from "./components/Divider";
 import { Tools } from "./components/Tools";
@@ -6,6 +7,29 @@ import { About } from "./components/About";
 import { Newsletter } from "./components/Newsletter";
 import { Footer } from "./components/Footer";
 
+const title = "einfach produktiv. – Produktivität darf sich leicht anfühlen";
+const description =
+  "Werkzeuge, Impulse und die 7-Tage-Challenge für Menschen mit Familie, Verantwortung und wenig Zeit. Mehr Klarheit und Fokus im Alltag – einfach produktiv.";
+
+export const metadata: Metadata = {
+  title,
+  description,
+  alternates: {
+    canonical: "/",
+  },
+  openGraph: {
+    title,
+    description,
+    url: "/",
+    images: ["/hero.png"],
+  },
+  twitter: {
+    title,
+    description,
+    images: ["/hero.png"],
+  },
+};
+
 export default function Home() {
   return (
     <>