refactor(docs): use shared @unom/app-ui/footer component

The docs footer was a hand-maintained mirror of the marketing site's. Both now
render the same @unom/app-ui/footer component, so they stay in sync. The shared
view themes itself through @unom/style tokens (which the docs already map onto
their Fumadocs surfaces), and a resolveHref hook rebases root-relative links
onto the marketing-site origin. Footer types now come from the library too.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs-site/src/lib/cms.ts

@@ -1,33 +1,21 @@
 // The docs reuse the punktfunk footer from the shared unom CMS (cms.unom.io).
-// The CMS is multi-tenant: footer is a per-tenant collection, so scope the read
-// to this project's tenant. Read-only GET, so a plain typed fetch rather than
-// pulling in the Payload SDK + generated types.
+// The footer shape comes from @unom/app-ui/footer so the docs and the marketing
+// site share one type. The CMS is multi-tenant: footer is a per-tenant
+// collection, so scope the read to this project's tenant. Read-only GET, so a
+// plain typed fetch rather than pulling in the Payload SDK + generated types.
+import type { FooterData } from '@unom/app-ui/footer'
+
 const CMS_URL = 'https://cms.unom.io'
 
 // This project's tenant in the shared CMS.
 const TENANT = 'punktfunk'
 
-export interface NavigationLink {
-  id?: string | null
-  label?: string | null
-  to?: string | null
-}
+export type { FooterData as Footer } from '@unom/app-ui/footer'
 
-export interface NavigationSection {
-  id?: string | null
-  title?: string | null
-  entries?: NavigationLink[] | null
-}
-
-export interface Footer {
-  tagline?: string | null
-  sections?: NavigationSection[] | null
-}
-
-export async function findFooter(): Promise<Footer | null> {
+export async function findFooter(): Promise<FooterData | null> {
   const query = `where%5Btenant.slug%5D%5Bequals%5D=${TENANT}&locale=en&depth=1&limit=1`
   const res = await fetch(`${CMS_URL}/api/footers?${query}`)
   if (!res.ok) throw new Error(`CMS footer request failed: ${res.status}`)
-  const data = (await res.json()) as { docs?: Footer[] }
+  const data = (await res.json()) as { docs?: FooterData[] }
   return data.docs?.[0] ?? null
 }