feat: expose governance authority address via precompile query

[abhijitkrm]

Description

This PR adds a getAuthority() view function to the governance precompile (0x0805) that returns the governance module account address in both Bech32 and EVM hex formats. This allows smart contracts and dApps to discover the authority address required for parameter-change and software-upgrade proposals without querying Cosmos LCD/gRPC endpoints out-of-band.

Previously, EVM-only dApps were limited to text/signaling proposals because the authority field required by MsgUpdateParams and MsgSoftwareUpgrade messages could not be determined on-chain.

Files to review

• precompiles/gov/IGov.sol — added getAuthority() to the Solidity interface
• precompiles/gov/abi.json — added the ABI entry
• precompiles/gov/query.go — added GetAuthorityMethod constant and GetAuthority function (derives via authtypes.NewModuleAddress(govtypes.ModuleName))
• precompiles/gov/gov.go — added GetAuthorityMethod case in the Execute switch
• precompiles/testutil/contracts/GovCaller.sol — added getAuthority() wrapper for contract-call tests
• tests/integration/precompiles/gov/test_query.go — unit test
• tests/integration/precompiles/gov/test_integration.go — integration test (direct + contract call)

How to review

1. Review the GetAuthority function in precompiles/gov/query.go — it derives the gov module account address and returns it in both Bech32 and hex formats.
2. Run the unit test: cd evmd && go test -tags=test -run "TestGovPrecompileTestSuite/TestGetAuthority" ./tests/integration/precompiles/gov/ -v
3. Run the integration tests: cd evmd && go test -tags=test -run "TestGovPrecompileIntegrationTestSuite" ./tests/integration/precompiles/gov/ -v
4. To verify end-to-end on a localnet, see the steps in the linked issue.

Closes: #1211

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• tackled an existing issue or discussed with a team member
• left instructions on how to review the changes
• targeted the main branch

[greptile-apps]

PR author is not in the allowed authors list.