fix: computePovwRate no longer double-skips the latest completed epoch

[zeroklaw]

Problem

computePovwRate in src/lib/parseEpochs.ts double-skips the latest completed epoch. The function uses slice(1, lookback + 1) to "skip the latest epoch" (the ongoing one), but the /api/epochs endpoint already excludes the ongoing epoch — it returns only completed epochs. This means slice(1) skips the most recent completed epoch instead, which is the most data-relevant point for the PoVW rate calculation.

Impact

With 99 completed epochs and a lookback of 10, computePovwRate was using epochs 2–11 (sorted desc) instead of epochs 1–10. The most recent completed epoch was always excluded.

Fix

Changed slice(1, lookback + 1) to slice(0, lookback) since the API already handles ongoing-epoch exclusion. Updated comments to reflect the correct behavior.

Testing

• Added regression tests in src/lib/parseEpochs.test.ts covering:
  • Most recent epoch is included in calculation
  • Exactly lookback number of epochs are used
  • Default lookback of 10 works correctly

Fixes #35

[github-actions]

Preview deployment

	URL
Latest commit	https://e6b9b91c.boundless-profit-explorer.pages.dev
Branch alias	https://head.boundless-profit-explorer.pages.dev

The branch alias URL always points to the latest commit on this PR.