feat: gate unfinished dashboard features

[numnx]

Summary

• add Vite-backed dashboard feature flags for unfinished dashboard surfaces, defaulting enabled in dev/test and disabled in production unless explicitly enabled
• gate the unfinished Nodes page across route registration, navigation, route prefetching, and the guided dashboard tour
• replace the CI mockup sprint pentest workflow with a mockup sprint orchestration workflow that runs pnpm run test:orchestration:full on pushes and PRs to dev and main
• update canonical docs and docs-web content for feature flags and the CI orchestration lane

Verification

• pnpm run lint passed
• pnpm run test:dashboard passed
• pnpm run test:backend passed
• pnpm run build passed
• pnpm exec vitest run tests/backend/services/docs-web-catalog-service.test.ts tests/dashboard/lib/dashboard-feature-flags.test.ts tests/dashboard/v2/nodes-page.test.tsx passed
• git diff --check passed
• pnpm run check:docs-web still reports pre-existing generated-docs drift in unrelated docs outputs:
  • content/docs/user-installation.mdx
  • content/docs/user-dashboard-chat.mdx
  • routes/docs.user-dashboard-nodes-canvas.lazy.tsx
  • content/docs/user-dashboard-memory.mdx
  • content/docs/developer-overview.mdx

Risk / Rollback

• Feature flag behavior is build-time dashboard configuration. Revert this PR or set VITE_CODEUX_FEATURE_NODES=true for a production dashboard build if the Nodes page needs to be exposed.
• CI behavior can be rolled back by restoring the previous mockup sprint pentest workflow if heavy pentest coverage needs to run in CI again.