Task 569: Fix route arrows misalignment with spacecraft movement

Status: DONE

Summary

Transfer arc endpoints were using planet positions at the mission epoch (day 0)

for all transfers, instead of the actual departure/arrival times. This caused

arcs to point at where planets were at mission start, not where they actually

were when the ship departed/arrived.

Root cause

• transferArcs were built from planets[] array which contains epoch positions
• Should use planetPositionAtTime(orbit, dayOffset) with actual JD offsets

Fix

• Moved timeline orbit construction before transfer arc construction
• Transfer arc endpoints now computed using planetPositionAtTime() with

correct day offsets (departure.jd - firstJd, arrival.jd - firstJd)

• Applied fix in all 3 code paths: data layer, inline template, standalone HTML

Tests added (1 new)

• orbital-3d-viewer-data.test.ts: verifies arc endpoints match planet

positions at departure/arrival times (100-day offset produces visible shift)

Files changed

• ts/src/orbital-3d-viewer-data.ts — time-correct arc endpoint computation
• ts/src/orbital-3d-viewer-data.test.ts — 1 new test
• ts/src/templates.ts — inline viewer arc fix
• ts/examples/orbital-3d.html — standalone viewer arc fix

Impact

• Human directive phase 30 item (4) addressed