Custom post content blocks (images/gallery/video/quote) + backend-driven SEO settings

RichText.tsx switched to Payload's official React renderer + custom
JSXConverters (same call signature, LiveRichText/LivePostContent
untouched) — needed to render the new Lexical Blocks the Payload repo's
Posts.content just gained. Converters follow the existing CMS-image
convention (relative + aspect-[...] + fill + object-cover); the video
block resolves YouTube/Vimeo links to an iframe embed.

New getSeoSettings() fetcher (same pattern as getKleinunternehmer()),
app/layout.tsx now generateMetadata() reading it with the same fallback
values it used to hardcode. Per-post SEO overrides (seoTitle/
seoDescription/seoImage) wired into the blog detail page's metadata,
falling back to title/excerpt/thumbnail when empty.

Also fixed while auditing every page's metadata: missing descriptions on
3 konto pages, a static title on the dynamic order-detail route, and
missing OG images on /shop and /blog.

README.md

@@ -1441,6 +1441,44 @@ calling out specifically since they add new shared components:
   each page's heading — not nested inside the sidebar's `hidden lg:...`
   wrapper, which would hide it too regardless of its own `lg:hidden` class.
 
+## Custom post content blocks, and SEO settings (2026-07-24)
+
+`app/components/RichText.tsx` switched from a small hand-rolled Lexical
+JSON→JSX walker to Payload's official `@payloadcms/richtext-lexical/react`
+renderer + custom `JSXConverters` — needed once the Payload repo's
+`Posts.content` gained custom Lexical Blocks (`Bild`/`Bildergalerie`/`Video`/
+`Zitat`, see the Payload README's own section on this), which the old
+hand-rolled `switch` had no case for at all. Kept the exact same exported
+call signature (`RichText({ content, quoteLabel })`), so `LiveRichText.tsx`
+and `app/blog/[slug]/components/LivePostContent.tsx` needed zero changes.
+`extractHeadings()`/`headingId()` (used by `SectionTOC` on legal pages) stay
+an independent, minimal walk over the raw JSON, unrelated to the new
+renderer — legal pages don't use Blocks.
+
+Block converters follow this project's established "CMS-sourced image"
+convention (`relative` + `aspect-[…]` + `next/image fill` + `object-cover`,
+see the blog thumbnail treatment) — a gallery block renders as a
+`grid-cols-2` grid, a video block resolves a YouTube/Vimeo URL into an
+`<iframe>` embed. The converters object is built fresh per `RichText()` call
+(a factory closing over that call's own `quoteLabel`), not a module-level
+constant — Server Components can render multiple posts concurrently in the
+same process, so a shared mutable variable would be a real race condition.
+
+**SEO settings** — new `getSeoSettings()` in `app/lib/payload.ts` (same
+ISR-cached, public-safe-subset-of-CompanySettings pattern as
+`getKleinunternehmer()`), with a hardcoded fallback equal to what used to be
+directly in `app/layout.tsx`. `app/layout.tsx`'s `metadata` export became
+`generateMetadata()` reading it. `PostDetail`/`mapPayloadPost`/
+`getPostBySlug()` gained `seoTitle`/`seoDescription`/`seoImage`, each
+falling back to the post's own `title`/`excerpt`/`thumbnail` when empty;
+`app/blog/[slug]/page.tsx`'s `generateMetadata()` uses them (now also
+setting a `twitter` block, previously missing). A few smaller gaps found
+while auditing every page's metadata were fixed in the same pass: 3
+`konto/*` pages were missing a `description`, `/konto/bestellungen/
+[orderNumber]` had a static "Bestelldetails" title despite being a dynamic
+route (now uses the real order number), and `/shop`/`/blog` were missing an
+Open Graph image.
+
 ## Tests
 
 `npm run test:unit` (Vitest, `node` environment, no jsdom/Next.js runtime