Add /impressum and /datenschutz pages backed by Payload

- lib/payload.ts: getLegalPage(type) alongside the existing
  getBlogPosts/getProducts fetchers
- New RichText component: small dependency-free Lexical JSON → JSX
  renderer for Payload's richText fields (headings get stable
  "section-N" ids for anchor/TOC linking)
- New SectionTOC: generalized from VersandTOC into a reusable
  scroll-spy sidebar driven by any {id, title}[] — Datenschutz needs one
  built from CMS-authored headings, not a hardcoded array. VersandTOC is
  now a thin wrapper around it. Sticky positioning moved from the nav
  itself to each page's sidebar wrapper, so a TOC and an extra card
  (Impressum/Datenschutz both have one) scroll together as one unit
  instead of the card drifting away independently
- TOC clicks set the active item immediately and hold it for ~1s over
  the scroll-spy observer, covering both "target already fully visible,
  nothing to scroll" and "an unrelated section flickers through the
  intersection band mid-scroll"
- Both pages follow the same breadcrumb+H1+TOC-sidebar+content layout
  established for /versand

app/components/SectionTOC.tsx

@@ -0,0 +1,94 @@
+"use client";
+
+import { useEffect, useRef, useState } from "react";
+
+export type TOCSection = { id: string; title: string };
+
+// How long a click "wins" over the scroll-spy observer — long enough to
+// cover the native smooth-scroll animation triggered by the anchor href,
+// so sections passing through the viewport mid-scroll can't flicker the
+// active state away from what was actually clicked.
+const CLICK_OVERRIDE_MS = 1000;
+
+// lg:-only sidebar — same "wide fixed-width block next to content" shape
+// as the cart's order-summary sidebar (see figma-to-nextjs skill Gotcha
+// #5): a 360px TOC card plus a readable content column already exceeds
+// the 768px Tablet floor, so md: wouldn't leave room for a real 2-column
+// split at Tablet widths.
+//
+// Generic over `sections` — originally written just for /versand
+// (VersandTOC), generalized once /datenschutz needed the identical
+// scroll-spy sidebar but driven by CMS-authored headings instead of a
+// hardcoded array. Any future long legal/content page reuses this too.
+//
+// Not sticky itself — Impressum/Datenschutz put an extra card below this
+// in the same sidebar column, and if only this <nav> were sticky, the
+// card (a plain-flow sibling) would scroll away independently instead of
+// travelling with it. The caller wraps whatever the sidebar column
+// contains (this alone, or this + more) in `lg:sticky lg:top-32
+// lg:self-start` so the whole column moves as one unit.
+export function SectionTOC({ sections }: { sections: TOCSection[] }) {
+  const [active, setActive] = useState<string>(sections[0]?.id ?? "");
+  // Not state — read inside the IntersectionObserver callback without
+  // needing to re-subscribe it on every click, and cleared by its own
+  // timeout rather than a render.
+  const overrideRef = useRef<string | null>(null);
+  const overrideTimeoutRef = useRef<ReturnType<typeof setTimeout> | undefined>(undefined);
+
+  useEffect(() => () => clearTimeout(overrideTimeoutRef.current), []);
+
+  useEffect(() => {
+    const observer = new IntersectionObserver(
+      (entries) => {
+        // A click just fired — trust it over whatever the scroll-spy sees
+        // mid-animation (sections flying past the intersection band while
+        // the browser's native smooth-scroll is still catching up to the
+        // clicked target), including the case where the target was
+        // already fully visible and no scroll happens at all.
+        if (overrideRef.current) return;
+        const visible = entries.filter((entry) => entry.isIntersecting);
+        if (visible.length > 0) setActive(visible[0].target.id);
+      },
+      { rootMargin: "-120px 0px -65% 0px", threshold: 0 }
+    );
+    sections.forEach(({ id }) => {
+      const el = document.getElementById(id);
+      if (el) observer.observe(el);
+    });
+    return () => observer.disconnect();
+  }, [sections]);
+
+  function handleClick(id: string) {
+    setActive(id);
+    overrideRef.current = id;
+    clearTimeout(overrideTimeoutRef.current);
+    overrideTimeoutRef.current = setTimeout(() => {
+      overrideRef.current = null;
+    }, CLICK_OVERRIDE_MS);
+  }
+
+  if (sections.length === 0) return null;
+
+  return (
+    <nav className="hidden lg:flex flex-col gap-1 w-[22.5rem] shrink-0 bg-bg-base border border-border rounded-md p-6">
+      <p className="text-label font-semibold text-text-muted uppercase tracking-wide mb-2">
+        Inhaltsübersicht
+      </p>
+      {sections.map(({ id, title }) => (
+        <a
+          key={id}
+          href={`#${id}`}
+          onClick={() => handleClick(id)}
+          className={
+            "px-3 py-2 rounded-sm text-body-sm transition-colors border-l-2 " +
+            (active === id
+              ? "border-toc-active-border bg-bg-muted text-text-primary font-semibold"
+              : "border-transparent text-text-muted hover:text-text-primary")
+          }
+        >
+          {title}
+        </a>
+      ))}
+    </nav>
+  );
+}