First-run health check for DeepSeek Harness.
- 8 checks: node/pnpm/dsh toolchain, home, profile, API key (names only), workspace, registry
- Actionable next steps; values never printed
- CLI + agent-callable quickstart tool, dsh-firstrun/v1 reports
- Windows shim-safe exec; 7 unit tests, packed integration, dsh web boot smoke