Add ETH RPC DAO pool balance alias

[andrewnguyen22]

This PR improves exchange-facing ETH-RPC compatibility for Canopy by exposing protocol balances through Ethereum-style reads.

Summary

• Adds canopy_getStake(address, blockTag?) to return validator stakedAmount as an eth_getBalance-style 18-decimal hex amount.
• Adds canopy_getPool(id, blockTag?) to return pool amount as an eth_getBalance-style 18-decimal hex amount.
• Adds a reserved read-only DAO pseudo-address alias:
  • eth_getBalance(0x000000000000000000000000000000000001ffff, < blockTag >)
  • Returns the DAO pool balance from DAOPoolID for centralized-exchange compatibility.
• Updates ETH-RPC documentation to describe the new custom methods and DAO pseudo-address behavior.

Why

• Some integrations, including exchange listing flows, expect an Ethereum-style address they can poll with eth_getBalance.
• Canopy pools are native protocol state, not EOAs, so this adds the smallest compatibility layer needed without broadening the ETH wrapper into a full pool-address model.
• The custom methods remain available as the explicit integration path for native stake/pool reads.

Implementation notes

• The DAO alias is scoped to a single reserved pseudo-address only.
• Normal eth_getBalance behavior for standard account addresses is unchanged.
• Missing validators in canopy_getStake return 0x0 to match eth_getBalance expectations.

Files changed

• cmd/rpc/eth.go
• cmd/rpc/README.md
• fsm/ethereum.md