Task 601: Add IF Counterfactual Orbital Diagrams to EP02-EP04

Status: DONE

Background

DESIGN.md specifies: "軌道遷移に複数パターンがある場合、ひとつの軌道遷移図で複数パターンを同時にアニメーションさせると比較がわかりやすい"

EP01 (ep01-diagram-04: perijove vs high-altitude capture) and EP05 (ep05-diagram-03: flyby vs direct route) already have multi-scenario IF comparison diagrams using the DiagramScenario + TransferArc.scenarioId infrastructure.

EP02, EP03, and EP04 had textual IF exploration blocks but NO visual IF orbital diagrams. This task added them.

Results

EP02: Saturn Moon Capture Comparison (ep02-diagram-04)

• Saturn-centric diagram with 3 scenarios: Enceladus (canonical, green), Rhea (IF, yellow), Titan (IF, purple)
• v∞=4.69 km/s hyperbolic approach → capture at each moon orbit
• Demonstrates Oberth effect: deeper gravity well = lower capture ΔV

EP03: Uranus Moon Destination Comparison (ep03-diagram-03)

• Uranus-centric diagram with 3 scenarios: Titania (canonical, green), Miranda (IF, blue), Oberon (IF, orange)
• Shows all 4 major Uranian moons + approach point
• Highlights infrastructure vs ΔV tradeoff

EP04: Plasmoid Avoidance Route (ep04-diagram-03)

• Uranus magnetosphere-scale diagram with 2 scenarios: Shield breakthrough (canonical, green), Engine avoidance (IF, red)
• Shows plasmoid zone, magnetopause, and departure/exit points
• Visualizes the shield-vs-engine decision that determines EP05 survival

Also fixed

• Pre-existing E2E test failure (3D viewer caption text mismatch)
• Added reference point IDs for new diagram markers

Stats

• TS tests: 4,139 → 4,175 (+36 including auto-generated diagram validation)
• E2E tests: 290 (all pass, 1 pre-existing failure fixed)
• Total tests: 4,960 → 4,996
• Tasks: 600 → 601