Merge pull request #321 from mocachain/chore/drop-dead-client-testnet

chore(client): delete the dead testnet.go duplicate

Author: puneet2019

CHANGELOG.md

@@ -62,6 +62,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 - (testutil) [#312](https://github.com/mocachain/moca/pull/312) Slim `testutil/`: delete dead helpers (`contract.go`, `integration.go`, `statedb.go`, `CreateEthTx`) and use `cosmos/evm/testutil`'s fork-neutral `NoOpNextFn`/`NewHeader` instead of the in-tree copies. Fork-coupled helpers (key/codec/signing, `testutil/network`, funding) are deliberately kept in-tree — swapping them would change which `ethsecp256k1` type tests exercise.
 - (proto) [#316](https://github.com/mocachain/moca/pull/316) Drop the orphaned `ethermint.feemarket.v1` protos and their generated `api/` pulsar code: zero importers since the in-tree `x/feemarket` was replaced by cosmos/evm's (`cosmos.evm.feemarket.v1`), and the dead protos were being republished to moca's BSR. `ethermint/types/v1/account.proto` stays — `EthAccount` is the stored account type.
 - (types,utils) [#320](https://github.com/mocachain/moca/pull/320) Delete dead ethermint-era files orphaned by the `rpc/`/`x/evm`/`x/erc20` removals: `types/{block,gasmeter,int,protocol,validation,constant}.go`, `types/openapiutil/`, and `utils/eth/eth.go` — every exported symbol verified unreferenced across the repo and all known external consumers (moca-storage-provider, moca-go-sdk, moca-challenger). Externally-used files (`chain_id.go` — `ParseChainID` is production code in the storage provider's signer — `grn.go`, `s3util`, `resource`, `common`) are untouched.
+- (client) [#321](https://github.com/mocachain/moca/pull/321) Delete the dead `client/testnet.go` (579 LOC): an unreferenced near-duplicate of `cmd/mocad/cmd/testnet.go`, which is what the `mocad testnet` command actually wires.
 - (contracts) [#314](https://github.com/mocachain/moca/pull/314) Slim `contracts/` to what moca actually uses (mirroring cosmos/evm's top-level `contracts/` convention): delete the four ERC20 test doubles (`MinterBurnerDecimals`, `Burnable`, `DirectBalanceManipulation`, `MaliciousDelayed`) — dead since the `x/erc20` removal (#221), available upstream where still needed — plus their `.sol` sources, artifacts, and npm manifest. The moca-specific `ERC721NonTransferable` (bucket/object/group NFT facade the storage keeper mints/burns through) stays put, now pinned by a guard test covering its ABI surface, fixed token/hub addresses, and its intentionally bytecode-less (ABI-only) nature. Slither retargets to `solidity/`; the now-subjectless solhint workflow and broken `lint-contracts` Make targets are removed.
 
 ### State Machine Breaking