Expand the OpenAPI spec from 11 to 39 endpoints covering Runs, Workflows,
Verifications, Retros, Sessions, Insights, Settings, and Projects with ~45
schemas. Add `--demo` flag to `arc serve` that serves static demo data for
all endpoints (auth disabled, read-only). Non-demo mode returns 501 for new
endpoints while existing run handlers continue working.
Regenerate the TypeScript API client and add `apiJson` helper. Wire all 19
React route files with server-side loaders that fetch from the API and map
snake_case responses to camelCase UI types. Mock data kept as fallback.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
