Task 578: Fix 3D Viewer dist Bug, Local Scene Arcs, Add E2E JS Error Test

Status: DONE

Description

1. Critical bug: dist variable used in addTransferArc() arrow helper sizing was

undefined after Task 577 refactoring removed the local dist calculation. Fixed by

recomputing dist = from.distanceTo(to) before the arrow helper.

1. Local scene arcs: arcControlPoint() assumed Sun-centric geometry, producing

near-straight arcs in planet-centric local scenes (saturn-ring, uranus-approach).

Added arcControlPointLocal() with lateral offset for flyby-style curvature.

1. Missing E2E test: The 3D viewer example page had no "loads without JS errors"

test, unlike all other interactive component examples. Added test.

Files

• ts/src/orbital-3d-viewer.js — fix dist bug, add arcControlPointLocal, scene-aware dispatch
• ts/e2e/examples.spec.ts — add JS error test for 3D viewer
• current_tasks/578_3d_viewer_bugfix_and_tests.md — this file