docs(site): landing v2 — narrative redesign (loop · gates · vocabulary) (#3090)

* docs(site): hero copy — AI-written apps narrative, correctness chain, ontology link

Replace the category-label hero ("a metadata protocol and TypeScript
toolkit") with the two-beat claim the objectos.ai homepage sets up
("AI writes the app. ObjectOS keeps it governable." → "AI writes the
app. ObjectStack is what it writes."):

- lead carries the mistake-catching chain (strict TypeScript + Zod +
  validation gate at authoring time; runtime enforces permissions/audit)
- proof strip: ~1% code surface · Typed, validated, governed · Self-host
- one-line ontology positioning linking to the objectos.ai essay
  ("the definition layer should be an open protocol you own")
- site <title> template drops the "Protocol" category word

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

* docs(site): landing v2 — spec-sheet design + core narrative sections

Full landing redesign in an engineering spec-sheet aesthetic (blueprint
grid, mono kickers, Bricolage Grotesque display, gradient second beat):

- hero artifact card tells the whole loop in one visual: requirement →
  Claude Code writes typed metadata (diff) → os validate ✓ → os dev preview
- 01 The loop: create-objectstack → describe (agent writes, gate rejects)
  → preview in browser; requirement changes run the same loop
- 02 The gates: typed / validated / reviewed / governed
- 03 The vocabulary: 12 metadata capabilities for enterprise software +
  the one-off-codebase contrast + stats strip (1,600+ schemas, 5 drivers,
  7 adapters, MCP)

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

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Co-authored-by: Jack Zhuang <277994282+os-zhuang@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: os-zhuang