Use inclusive ramp-start condition in initial pledge calculation

[coderabbitai]

Summary

Update the initial pledge ramp-start condition in src/rpc/methods/state.rs to use an inclusive comparison (<=) where Forest aligns with the Lotus reference implementation.

Rationale

The current condition differs from Lotus. The inclusive boundary affects the ramp-start epoch calculation for initial pledge values.

Affected area

• src/rpc/methods/state.rs
• compute_initial_pledge_for_power and the ramp-start epoch handling

Required change

Compare the Forest condition with the referenced Lotus implementation and change the condition to the inclusive form when the semantics match.

Acceptance criteria

• Forest uses the inclusive ramp-start condition consistent with Lotus.
• The initial pledge calculation uses the correct ramp parameters at the boundary epoch.
• Add or update a focused regression test for the boundary epoch, if practical.

References

• Pull request: feat: impl Filecoin.StateMinerCreationDeposit #7495
• Review discussion: feat: impl Filecoin.StateMinerCreationDeposit #7495 (comment)
• Lotus reference: https://github.com/filecoin-project/lotus/blob/533aaa91772d55879d5898a0a49f75f51b671ab9/node/impl/full/state.go#L1444

Requested by: @LesnyRumcajs