- Add `require(averageTaxRate <= 1e18, "Invalid tax rate")` to match
the existing `percentageStaked` guard and prevent silent acceptance
of out-of-range values.
- Expand contract-level NatSpec with a @dev note clarifying this is an
equivalence proof only: it intentionally exposes `isBullMarket` alone
and is not a deployable upgrade (full optimizer interface missing).
All 15 Foundry tests pass (15 unit + fuzz).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>