feat: Add Hedera wallet provider

[aite550659-max]

Summary

Adds HederaWalletProvider for Hedera network support in AgentKit.

Features

• HBAR transfers - Send HBAR between accounts
• HCS messaging - Create topics and submit/read messages via Hedera Consensus Service
• Account balance - Query HBAR and token balances
• EVM address - Get the EVM-compatible address derived from the Hedera account

Why Hedera for Agents?

• $0.0001 transactions - Affordable for high-frequency agent operations
• 3-second finality - Fast enough for real-time agent interactions
• Native accounts - Real accounts, not smart contract wallets
• HCS messaging - Built-in consensus messaging for agent coordination
• aBFT security - Enterprise-grade security (hashgraph consensus)

Usage

import { HederaWalletProvider } from '@coinbase/agentkit';

const wallet = await HederaWalletProvider.configure({
  accountId: '0.0.12345',
  privateKey: 'your-ecdsa-private-key',
  network: HEDERA_MAINNET_NETWORK,
});

// Get balance
const balance = await wallet.getBalance();
console.log(balance.hbar);

// Transfer HBAR
await wallet.transfer('0.0.67890', 10);

// HCS messaging
const topic = await wallet.createTopic('Agent Channel');
await wallet.submitMessage(topic.topicId, { hello: 'world' });

Context

This PR was created as part of building agent-to-agent communication infrastructure. We completed the first real-value agent-to-agent cryptocurrency transfer on Hedera mainnet tonight and want to make it easy for other agents to use Hedera.

Testing

• Unit tests (to be added)
• Manual testing with mainnet wallet

Related

• Hedera SDK: https://github.com/hashgraph/hedera-sdk-js
• Hedera docs: https://docs.hedera.com

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 1 Sum 2