skills: refresh elegant-reports and add smoke test

[jdrhyne]

Summary

Refresh skills/elegant-reports from the cleaned public clone and add a minimal verification path so the skill can be merged/published without carrying local-machine baggage.

What actually changed

• replaced the older elegant-reports repo copy with the cleaned public version
• removed machine-specific/auth-loading behavior from generate.js
  • removed the fallback read from ~/clawd-nuri-internal/config/mcporter.json
  • removed the hard-coded ~/nuri_workspace/... sandbox path
  • now uses os.tmpdir() for sandbox output and requires NUTRIENT_DWS_API_KEY explicitly via env
• cleaned skill metadata/docs
  • removed Nuri-specific author/examples
  • replaced local paths like ~/clawd-nuri-internal/... with generic instructions
  • moved design research into references/nordic-design-research.md
• removed checked-in generated output artifacts
  • deleted examples/sample-output.html
  • deleted examples/sample-output.pdf
• added a tiny smoke test at skills/elegant-reports/scripts/smoke-test.js
  • verifies every template/theme pair loads and renders a full HTML document
  • does not require a live Nutrient API key
• added CI workflow .github/workflows/elegant-reports-smoke.yml
  • runs on PRs/pushes that touch skills/elegant-reports/**
  • installs dependencies and runs npm test
• refreshed supporting templates/theme assets included in the clean clone

Why

The previous checked-in version still contained private/local environment assumptions (mcporter, clawd-nuri-internal, nuri_workspace) and generated sample artifacts. This PR makes the published skill safer and cleaner to clone, while adding a lightweight non-network validation step.

Validation

• npm --prefix skills/elegant-reports test
• node skills/elegant-reports/generate.js --list
• hygiene grep for local/private refs in skills/elegant-reports
• npm pack --dry-run from skills/elegant-reports