feat: add Playwright E2E coverage and improve ribbon line-type workflows

[mlightcad]

Summary

• Add Playwright-based end-to-end testing for cad-viewer-example, including config, smoke tests, and a DXF fixture.
• Extend CI to install Playwright Chromium, run e2e tests, and upload Playwright artifacts on failure.
• Improve ribbon property behavior so color, line weight, and line type changes apply to currently selected entities.
• Enhance line type option rendering with inline SVG previews and increase ribbon property field width for better display.
• Bump @mlightcad/data-model and @mlightcad/libredwg-converter versions and refresh lockfile entries.

Why

• Provide automated browser-level regression coverage for core viewer loading and interaction flows.
• Ensure property edits from the ribbon affect selected entities immediately, matching user expectations.
• Improve line type preview fidelity beyond gradient-only fallbacks.
• Keep dependency versions aligned with newer CAD stack releases.

What Changed

• CI:
  • Update .github/workflows/ci.yml with Playwright browser install, e2e execution, and artifact upload.
• Example app testing:
  • Add playwright.config.ts.
  • Add e2e/tests/smoke.spec.ts (upload screen, DXF load/render shell, basic mouse interactions with runtime error capture).
  • Add e2e/fixtures/minimal-line.dxf.
  • Add e2e scripts and @playwright/test dev dependency in packages/cad-viewer-example/package.json.
• Viewer UI logic:
  • Add reusable selected-entity mutation helper in MlRibbonCommands.vue.
  • Apply ribbon color/lineweight/linetype updates to selected entities and trigger modified events.
  • Add previewSvgString support and resilient SVG extraction in lineTypeOptions.ts.
  • Render SVG previews in MlLineTypeSelect.vue with fallback background behavior.
  • Widen property field column in MlRibbonPropertyField.vue for improved content fit.
• Dependencies:
  • Update root overrides in package.json and lockfile to @mlightcad/data-model@^1.7.22 and @mlightcad/libredwg-converter@^3.5.22.

Risks / Notes

• v-html is used for line type SVG preview rendering; safety depends on trusted/sanitized SVG sources.
• CI runtime may increase due to browser installation and e2e execution.
• E2E tests currently focus on smoke coverage; deeper interaction/render assertions may be added later.