Add shop, cart, versand pages and Impulse & Tipps detail page

- New /shop overview, /cart (real cart state via useSyncExternalStore),
  /versand (shipping policy page with TOC) and /newsletter detail page
- Cart: quantity/removal, order summary, related-products cross-sell
  with randomized picks, VersandModal quick-reference instead of
  navigating away, MwSt. disclosure next to unit prices
- Add-to-cart UX: inline success feedback (green state) plus a
  fly-to-navbar-cart-icon animation (CartFlyProvider) with a delayed
  badge count-up; AddToCartButton no longer navigates straight to /cart
- Shared lib/products.ts catalog and lib/shipping.ts constants (cost,
  free-shipping threshold, handling/transit days) so cart, trust badges
  and the versand page can never drift apart
- Fix Navbar smooth-scroll easing (ease-out instead of ease-in-out, no
  more perceived start delay); compress newsletter modal photo
  2.4MB -> 85KB to fix first-open jank

app/components/TrustRow.tsx

@@ -0,0 +1,35 @@
+import { FREE_SHIPPING_THRESHOLD, TOTAL_DAYS_DE } from "../lib/shipping";
+import { formatPrice } from "../lib/products";
+
+const items = [
+  {
+    icon: "/icon-trust-shipping.png",
+    title: "Schneller Versand",
+    desc: `In ${TOTAL_DAYS_DE.min}–${TOTAL_DAYS_DE.max} Werktagen bei dir.`,
+  },
+  {
+    icon: "/icon-trust-free-shipping.png",
+    title: "Versandkostenfrei",
+    desc: `Ab ${formatPrice(FREE_SHIPPING_THRESHOLD)} Bestellwert innerhalb DE.`,
+  },
+  { icon: "/icon-trust-heart.png", title: "Mit Liebe verpackt", desc: "Für mehr Freude beim Auspacken." },
+];
+
+export function TrustRow() {
+  return (
+    <div className="w-full bg-bg-base flex flex-col md:flex-row gap-6 md:gap-12 items-center justify-center py-8 px-[var(--layout-padding-x)]">
+      {items.map((item, i) => (
+        <div key={item.title} className="flex items-center gap-6 md:gap-12">
+          {i > 0 && <div className="hidden md:block h-10 w-px bg-border" />}
+          <div className="flex gap-4 items-center">
+            <img alt="" src={item.icon} className="size-8 shrink-0 object-contain" />
+            <div className="flex flex-col gap-0.5 items-start">
+              <p className="font-semibold text-body text-text-primary whitespace-nowrap">{item.title}</p>
+              <p className="text-body-sm text-text-muted whitespace-nowrap">{item.desc}</p>
+            </div>
+          </div>
+        </div>
+      ))}
+    </div>
+  );
+}