Task 616: Fix Ship Animation in Local Encounter 3D Scenes

Status: DONE

Problem

Ship marker is invisible and appears non-animated in local encounter scenes:

• jupiter-capture: All timeline screenshots (t000/t050/t100) look identical
• earth-arrival: All timeline screenshots look identical
• saturn-ring, uranus-approach: Likely same issue

Task 615 fixed ship visibility for full-route and episode scenes but set local scene ship radius to 0.15 which is too small. The animation may also not be working — ship position appears static across timeline frames.

Investigation Plan

1. Examine the updateTimelineFrame() code path for local scenes (uses _sceneTransferArcs fallback)
2. Check if transfer arcs provide proper fromPos/toPos for interpolation
3. Determine correct ship marker size for each local scene type
4. Fix animation and verify with screenshots

Files to Examine

• ts/src/orbital-3d-viewer.js — updateTimelineFrame() local scene path
• ts/src/orbital-3d-viewer-data.ts — prepareLocalScene() transfer arc data