feat: plakat redesign for subpages (projects, books, legal, privacy)

- Shared SubpageShell (HeaderClient paper strip + ink footer) and SubpageIntro,
  btn/ghost/card helpers in app/_ui/subpage.tsx
- Projects list: poster cards with hard ink shadows, filter pills, ink search field;
  no fake 800ms skeleton and no framer-motion opacity:0 in SSR
- Project detail: poster hero, .plakat-prose markdown, links/stack aside,
  back link works without JS
- Books: server-side fetch (visible without JS), cover + rating pills
- Legal notice / privacy: moved to app/_ui/*Client.tsx, root routes removed
  (middleware always redirects to /[locale]), consent reset via useConsent
- ProjectThumbnail rebuilt on Plakat tokens
- Old Header.tsx + test removed; brown/cream/sand palettes and unused
  glass-panel/admin-glass(-light)/liquid-bg-blob/float CSS dropped
  (liquid palette, glass-card, admin-glass-card stay for admin + 404)
- .plakat-prose replaces the missing typography plugin

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/[locale]/legal-notice/page.tsx

@@ -1,6 +1,7 @@
 import type { Metadata } from "next";
 import { getLanguageAlternates, toAbsoluteUrl } from "@/lib/seo";
-export { default } from "../../legal-notice/page";
+import SubpageShell from "@/app/_ui/SubpageShell";
+import LegalNoticeClient from "@/app/_ui/LegalNoticeClient";
 
 export async function generateMetadata({
   params,
@@ -10,6 +11,7 @@ export async function generateMetadata({
   const { locale } = await params;
   const languages = getLanguageAlternates({ pathWithoutLocale: "legal-notice" });
   return {
+    title: locale === "de" ? "Impressum – Dennis Konkol" : "Legal notice – Dennis Konkol",
     alternates: {
       canonical: toAbsoluteUrl(`/${locale}/legal-notice`),
       languages,
@@ -17,3 +19,12 @@ export async function generateMetadata({
   };
 }
 
+
+export default async function Page({ params }: { params: Promise<{ locale: string }> }) {
+  const { locale } = await params;
+  return (
+    <SubpageShell locale={locale}>
+      <LegalNoticeClient />
+    </SubpageShell>
+  );
+}