feat: case-study template, all pages, routing, sitemap, 404

- case-study components: CsHeader, TldrBox, MiniToc, SectionRenderer, DecisionList,
  ArchDiagram (data-driven), Gallery, NextPrev, CaseStudyPage
- standalone pages: projects index, about, experience, contact (with form),
  cv hub, colophon — all EN/NO compositions
- full route tree: EN root + /no localised slugs (prosjekter, om-meg, erfaring,
  kontakt, kolofon, hjemmelab) per ROUTING_SPEC
- bilingual 404 with trace-fray motif; robots.txt + sitemap.xml from slug map
- Portrait atom; reusable sections gain header/eyebrow toggles for standalone pages

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

site/src/components/home/ExperienceTimeline.astro

@@ -7,9 +7,9 @@ import SectionLabel from '@components/ui/SectionLabel.astro';
 
 interface Props {
   locale: Locale;
-  compact?: boolean; // when true (experience page), render heading differently
+  eyebrow?: boolean; // false on the standalone experience page (it has its own H1)
 }
-const { locale } = Astro.props;
+const { locale, eyebrow = true } = Astro.props;
 const d = useDict(locale);
 const items = getExperience(locale);
 const firstAlongside = items.findIndex((i) => i.alongside);
@@ -17,9 +17,19 @@ const firstAlongside = items.findIndex((i) => i.alongside);
 const period = (from: number, to: number | null) => `${from}–${to ?? d.home.present}`;
 ---
 
-<section id={homeAnchor('experience', locale)} class="mx-auto max-w-[--content-max] px-6 pt-24" data-reveal>
-  <SectionLabel number="03" text={d.home.experienceLabel} />
-  <h2 class="mt-4 text-h2">{d.home.experienceHeading}</h2>
+<section
+  id={homeAnchor('experience', locale)}
+  class:list={['mx-auto max-w-[--content-max] px-6', eyebrow && 'pt-24']}
+  data-reveal
+>
+  {
+    eyebrow && (
+      <>
+        <SectionLabel number="03" text={d.home.experienceLabel} />
+        <h2 class="mt-4 text-h2">{d.home.experienceHeading}</h2>
+      </>
+    )
+  }
 
   <div class="relative mt-10 pl-8">
     <span