Task 556: Add animation to Saturn/Uranus local 3D scenes

Status: DONE

Summary

Added timeline animation data to Saturn and Uranus local 3D scenes. Previously only the

full-route scene had animation. Now moons (Enceladus, Titania) orbit their parent planets

and the ship approach arc is animated.

Changes

1. Added MOON_PERIODS_DAYS constants (Enceladus: 1.37d, Titania: 8.71d)
2. prepareSaturnScene now returns timeline with Enceladus orbit (3 orbital periods)
3. prepareUranusScene now returns timeline with Titania orbit (3 orbital periods)
4. Renderer loadTimeline handles local scene transfer arcs via _sceneTransferArcs
5. Example HTML: timeline controls work for all scenes (was hardcoded to full-route)

Tests added/modified (5 changes)

• orbital-3d-viewer.test.ts: replaced 2 "no timeline" tests with 3 tests checking local timelines
• orbital-3d-viewer-data.test.ts: 2 new tests for Saturn/Uranus timeline orbit data

Files changed

• ts/src/orbital-3d-viewer-data.ts — MOON_PERIODS_DAYS, timeline in Saturn/Uranus scenes
• ts/src/orbital-3d-viewer-data.test.ts — 2 new tests (31→33)
• ts/src/orbital-3d-viewer.test.ts — 3 new tests replacing 2 old (45→46)
• ts/src/orbital-3d-viewer.js — _sceneTransferArcs, local scene transfer curve fallback
• ts/examples/orbital-3d.html — timeline data for local scenes, activeTimeline tracking

Impact

• Stats: 4,029 TS tests
• Human directive phase 29 item (1) addressed: all scenes now have animation