Task 561: Add inline 3D viewers to EP03 and EP05 episode reports

Status: DONE

Summary

Added inline 3d-viewer: directive support to the episode MDX parser and

embedded 3D viewers in EP03 (Saturn ring scene) and EP05 (Uranus approach scene).

Also refactored the viewer3d script generation into a shared function used by

both episode and summary templates.

Changes

1. Type: Added viewer3d?: Viewer3DEmbed to EpisodeReport interface
2. Parser: Added 3d-viewer to episode parser fence regex + applyReportDirective
3. Template: Extracted generateViewer3dScript(basePath) shared function,

used by both renderEpisode and renderSummary

1. EP03: Added saturn-ring scene 3D viewer in preamble
2. EP05: Added uranus-approach scene 3D viewer in preamble
3. Validation: Updated directive validation test to include 3d-viewer

Tests added

• episode-mdx-parser.test.ts: 2 new tests (extracts + parses 3d-viewer)
• reports.spec.ts: 7 new E2E tests (EP03 scene/controls/TOC, EP05 scene/controls/TOC, EP01 no viewer)

Files changed

• ts/src/report-types.ts — viewer3d field on EpisodeReport
• ts/src/episode-mdx-parser.ts — 3d-viewer directive support
• ts/src/episode-mdx-parser.test.ts — 2 new parser tests
• ts/src/templates.ts — generateViewer3dScript shared function + episode rendering
• ts/src/article-content-validation.test.ts — updated directive set
• ts/e2e/reports.spec.ts — 7 new E2E tests
• reports/data/episodes/ep03.md — 3d-viewer directive (saturn-ring)
• reports/data/episodes/ep05.md — 3d-viewer directive (uranus-approach)

Impact

• Stats: 4,033 TS, 282 E2E (4,846 total)
• EP03 and EP05 now have interactive 3D orbital viewers