Task 439: Export G0_MS2 Standard Gravity Constant

Status: DONE

Summary

The literal 9.80665 (standard gravity in m/s²) appears ~17 times across all 5 episode analysis files. kestrel.ts already uses it internally but does not export it. Export G0_MS2 from kestrel.ts and replace all analysis-file occurrences.

Files to Change

1. ts/src/kestrel.ts — add export const G0_MS2 = 9.80665;
2. ts/src/ep01-analysis.ts — replace ~6 occurrences
3. ts/src/ep02-analysis.ts — replace ~6 occurrences
4. ts/src/ep03-analysis.ts — replace ~3 occurrences
5. ts/src/ep04-analysis.ts — replace ~3 occurrences
6. ts/src/ep05-analysis.ts — replace ~1 occurrence