Governance authority address not exposed via EVM precompile

[abhijitkrm]

Problem

The governance precompile (0x0805) allows submitting proposals via submitProposal, which accepts a JSON envelope containing messages. For parameter-change proposals (e.g. /cosmos.staking.v1beta1.MsgUpdateParams) and software upgrade proposals (/cosmos.upgrade.v1beta1.MsgSoftwareUpgrade), each message requires an authority field set to the governance module account's Bech32 address.

This address is deterministic — derived from authtypes.NewModuleAddress(govtypes.ModuleName) — but it is not exposed by any EVM precompile query. Smart contracts and dApps interacting with the governance precompile have no way to discover this address on-chain. They must either:

1. Hardcode the address (breaks on chains with different bech32 prefixes)
2. Query the Cosmos LCD/gRPC endpoint out-of-band (not possible from within a smart contract)

This effectively limits EVM-only dApps to text/signaling proposals (empty messages array), since parameter-change and software-upgrade proposals cannot construct valid messages without the authority address.

Reproducibility

1. Start a localnet (./local_node.sh)
2. Try to submit a parameter-change proposal from a smart contract using the gov precompile
3. The contract has no way to discover the authority address needed for MsgUpdateParams — it must be hardcoded or fetched off-chain

# The authority address is deterministic but not queryable on-chain:
cast call 0x0000000000000000000000000000000000000805 "getParams()" --rpc-url http://localhost:8545
# Returns params, but no authority address

Potential Impact

• Severity: Medium — blocks an entire class of proposals from EVM contracts
• User scope: All EVM dApps using the governance precompile
• Downstream effects: Parameter changes and software upgrades cannot be proposed from smart contracts

Proposed Solution

Add a new view query getAuthority() to the governance precompile that returns the governance module account address in both Bech32 and EVM hex formats. This is a non-breaking, read-only addition.