Task 602: Add IF Counterfactual Routes to 3D Viewer

Status: DONE

Summary

Extend the 3D orbital viewer to show IF (counterfactual) routes alongside canonical transfer arcs. Currently only 2D SVG diagrams support multi-scenario display (via DiagramScenario[] and TransferArc.scenarioId). The 3D viewer shows canonical routes only.

Scope

• Extend TransferArcData and SceneData types with scenario/IF fields
• Add IF arc definitions to prepareEpisodeScene() for relevant episodes
• Add scenario toggle UI to the 3D renderer (show/hide IF arcs)
• Update inline __prepareScene in templates.ts
• TDD approach: tests first

Key Files

• ts/src/orbital-3d-viewer-data.ts — scene data preparation
• ts/src/orbital-3d-viewer.js — Three.js renderer
• ts/src/report-types.ts — types
• ts/src/templates.ts — inline scene prep + renderViewer3D()
• ts/src/orbital-3d-viewer-data.test.ts — data tests
• reports/data/episodes/ep0[1-5].md — 3d-viewer directives

IF Scenarios per Episode (from 2D diagrams)

• EP01: Direct route (no Oberth maneuver) — already in ep01-diagram-03
• EP02: Enceladus (canonical) vs Rhea/Titan destination — ep02-diagram-04
• EP03: Titania (canonical) vs Miranda/Oberon destination — ep03-diagram-03
• EP04: Shield breakthrough (canonical) vs engine avoidance — ep04-diagram-03
• EP05: Jupiter flyby necessity — ep05-diagram-03

Dependencies

• Task 601 (2D counterfactual diagrams) — DONE
• Task 587 (2D/3D alignment TDD) — DONE