feat: core layout, UI atoms, homepage + behaviour modules

- UI atoms: Chip, Button, SplitCvButton, LangSwitch, ThemeToggle, Card,
  SectionLabel, TraceMotif, FramedImage
- core: Base/Seo/Header/MobileNav/Footer/HintBar/SkipLink/ThemeScript
- homepage sections: Hero, ProofStrip, SkillsGrid, ProjectCards,
  ExperienceTimeline, AboutTeaser, ContactBand + Homepage composition (EN/NO)
- behaviour modules: theme, nav (overlay/hint/copy/header), observer (reveal/spy),
  lightbox, form — progressive enhancement, fail-silent
- SEO head component: meta, hreflang from slug map, JSON-LD, OG references
- move content data to src/data (avoid Astro reserved content-collection folder)

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

site/src/i18n/dictionary.en.ts

@@ -1,6 +1,21 @@
 import type { Dictionary } from './dictionary';
 
 export const en: Dictionary = {
+  hero: {
+    viewProjects: 'View projects',
+  },
+  home: {
+    skillsLabel: 'Skills',
+    skillsHeading: 'What I work with',
+    skillsIntro: 'A practical profile: business value, maintainability and dependable delivery.',
+    projectsLabel: 'Projects',
+    projectsHeading: 'Built, shipped and running',
+    experienceLabel: 'Experience',
+    experienceHeading: 'Where I’ve worked',
+    aboutLabel: 'About',
+    earlierRoles: 'Earlier & alongside',
+    present: 'Present',
+  },
   nav: {
     home: 'Home',
     projects: 'Projects',