chore: bump cosmos/evm to derived-tx gas price fix

[0xNilesh]

Bumps the cosmos/evm pin to pick up push-chain-evm#37.

- github.com/cosmos/evm => github.com/pushchain/evm v1.0.0-rc2.0.20260627105801-6c22ba0b1e9e
+ github.com/cosmos/evm => github.com/pushchain/evm v1.0.0-rc2.0.20260803072921-2d248e1881bb

What it fixes

Blocks whose only content is derived transactions (protocol-internal, not user-signed) render a
negative block reward in explorers. Derived txs are reconstructed from ABCI events, which carry no
fee data, so they are rebuilt with GasFeeCap = GasTipCap = 0 and the EIP-1559 formula resolves their
price to 0 — while the receipt still reports gasUsed > 0.

Blockscout computes a block's reward as Σ(gas_used × gas_price) − base_fee × Σ(gas_used), which for a
derived-only block goes negative. Reproduced on live donut (block 0x13a5ce8):

effectiveGasPrice 0x0 · gasUsed 0xb2dc · baseFeePerGas 0x3b9aca00
reward = 45788×0 − 1e9×45788 = -45,788,000,000,000

The fix reports the block base fee as the derived tx's gasPrice and receipt effectiveGasPrice, so
the arithmetic nets to exactly zero — matching the chain's real economics, since a derived tx pays
nothing to the proposer and burns nothing.

JSON-RPC reporting only — no consensus, no state changes.

Scope

go.mod + go.sum only. go build ./... clean.

An upgrade simulation from release/v1.1.38-donut (currently deployed on donut) to this branch was run
locally to validate the binary swap. No upgrade handler is required or included — the change is not
state-breaking.