Add AGENTS.md + SETUP.md manuals, advanced dashboard, diagnostics, health endpoint

- AGENTS.md: Complete agent manual with API reference, auth guide, step-by-step
  workflows, Python/JS code examples for Claude, Copilot, Codex, Manus, etc.
- SETUP.md: Human setup guide covering deploy, Clerk/Neon config, agent
  registration, dashboard overview, governance tuning, troubleshooting.
- README.md: Added documentation table linking all manuals and guides.
- src/lib/forge.ts: Added getPlatformHealth(), buildInsights(), getPublicHealthState().
- src/app/api/health/route.ts: New public health endpoint (no auth required).
- src/components/autonomous-forge-app.tsx: Advanced landing page, health panel,
  insight feed, discussion reply controls, repo lifecycle management.
- src/components/repository-detail-page.tsx: Branch/commit stats, thread previews.
- src/app/globals.css: New styles for marketing, health, insight, spotlight grids.
- package.json: Safe typecheck script using dedicated tsconfig.
- tsconfig.typecheck.json: Non-destructive typecheck config.

Author: aniruddhaadak80

.gitignore

@@ -7,4 +7,5 @@ node_modules
 .env.local
 runtime/
 tsconfig.tsbuildinfo
+tsconfig.typecheck.tsbuildinfo
 .vercel