Prod - Astro v6 and redesign update

v4.0.0 — UI Redesign + Production Hardening

✨ Design

• Full homepage + inner page redesign with modern hero and masked-clip typography animation
• Directional page transitions via Astro ClientRouter with motion tokens
• Blog index overhaul — tag/sort/direction filtering with URL sync

📝 Content

• New post: Tech Layoffs & the Economy with 5 inline SVG data visualizations

🔒 Security

• CSRF bypass fix — exact origin match (Set.has()) instead of startsWith()
• Rate limiter memory leak fix — rateLimitMap pruned at 1000 entries
• Redis rate limit fallback no longer silently bypassed when multi() unavailable
• Sentry trace sample rate reduced to 0.1 in production

⚙️ Infrastructure

• Upgraded: Astro 6.3.1, Tailwind CSS v4, React 19, TypeScript 6
• Vercel build fix — removed stale pnpm-lock.yaml, declared packageManager: bun@1.3.13
• Sentry sourcemaps scoped to dist/_astro/ only (was matching server chunks)
• varlock — env schema with full type/sensitivity annotations, typegen on build, secret scan on pre-commit

🔍 SEO

• Canonical link always rendered (was conditionally gated)
• Fixed robots.txt Allow/Disallow ordering that blocked sitemaps for non-Googlebot crawlers
• Added WebSite schema with SearchAction for Google Sitelinks Searchbox

♿ Accessibility

• Skip-to-main-content link added to root layout
• .btn-primary color contrast fixed (1.5:1 → 12:1)
• Mobile nav touch targets raised to 44px minimum (WCAG 2 AA)

🛠 DX

• README rewritten — accurate stack table, env var reference, concise scripts
• demo.gif updated with new design