feat(evm): initial foundation - design, crypto primitives and address/hash types

[atharrva01]

First slice of the EVM network driver (Approach 2). This locks in the design we hammered out on #1701 and adds the basic crypto layer everything else will build on. No actual driver logic yet.

What's included

• Updated design doc with the decisions we settled on: single-list StateDelta with a contract-side graphHiding flag, tokenID-only spend refs (since the EVM contract is stateful, we don't need to bind the token hash into the key like Fabric does), SHA-256 for request/public-params hashes, and quorum governance once the deployer seeds the initial state.
• Crypto helpers: keccak256 (via x/crypto/sha3) and SHA-256. The SHA-256 one matches the SDK's token-request hash so finality lines up later.
• Local Address (20B) and Hash (32B) types with hex/text/JSON encoding. No go-ethereum dependency, plus a build test that fails if it ever sneaks in (license issue for us).
• Basic package scaffolding under x/token/services/network/evm.
• Small go.sum fix in the integration module (missing badger entry) so the build works again.

Not in this PR

StateDelta types, key derivation, EIP-712, and driver wiring are coming in follow-up PRs.

[AkramBitar]

@atharrva01

Thanks a lot for submitting this PR. Could you please open corresponding issue for it and link it to this PR?

Regards,
Akram

[atharrva01]

Hi @AkramBitar , this is LFX project , and this is the foundation pr of the etherum driver I m building , so how can I open a issue for it ? For each pr ?