feat(site): port stitch design system + seed-ready content model

Ports the "Technical Editorial" design sample into real TSX wired to
Payload globals/collections. Home/About/Projects (list+detail)/Contact
pages render against Payload data. Expands schemas (Home principles,
About timeline/skills/gear, Contact channels) to cover the full design
surface. Adds seed script that populates realistic AI-drafted content
for first boot. Defers writing/resume routes per scope cut.

- Design tokens: Material-3 palette + Space Grotesk/Inter typography
  scale + dot-grid + glassmorphism utilities
- Shared layout: Nav, Footer, StatusTerminal, GridOverlay, Button,
  TechChip in src/components/site
- Schemas: expand 5 globals + 6 collections; add auto-slug hook
- Seed: scripts/seed.ts — idempotent upsert for media, categories,
  6 projects, 8 gear, 3 posts, 5 globals; generates placeholder admin
- Contact: form + /api/contact route with optional Turnstile verify
- Rename TURNSTILE_SITE_KEY -> NEXT_PUBLIC_TURNSTILE_SITE_KEY (client)
- Remove dead src/components/SiteHeader|SiteFooter|StatusTerminal

package.json

@@ -14,9 +14,11 @@
     "payload": "payload",
     "generate:types": "payload generate:types",
     "generate:importmap": "payload generate:importmap",
-    "test": "echo \"no tests yet\" && exit 0"
+    "test": "echo \"no tests yet\" && exit 0",
+    "seed": "tsx scripts/seed.ts"
   },
   "dependencies": {
+    "@marsidev/react-turnstile": "^1.5.0",
     "@payloadcms/db-postgres": "^3.50.0",
     "@payloadcms/next": "^3.50.0",
     "@payloadcms/richtext-lexical": "^3.50.0",
@@ -41,6 +43,7 @@
     "eslint-config-next": "16.1.6",
     "postcss": "^8.5.0",
     "tailwindcss": "^3.4.17",
+    "tsx": "^4.19.4",
     "typescript": "^5.7.3"
   },
   "engines": {