Feature/hip1190 sign transactions

[omar-hgraph]

HIP-1190: ECDSA/Ed25519 Wallet Support

Overview

Critical fix enabling HIP-1190 multi-node transaction signing to work correctly with both ECDSA (EIP155) and Ed25519 (native Hedera) accounts.

Problem Statement

hedera_signTransactions was failing with invalid signature errors when invoked by EIP155/ECDSA accounts, while other Hedera methods (hedera_signMessage, hedera_signTransaction) worked correctly.

Root Cause:

• When ECDSA accounts connected via EIP155 namespace, they could also use Hedera namespace methods
• The wallet had only one HIP820Wallet instance initialized with Ed25519 key
• When hedera_signTransactions was called on an ECDSA session, it used the wrong key (Ed25519 instead of ECDSA)
• Result: Signature mismatch and transaction rejection

Solution

Implement dual HIP820 wallet instances with intelligent routing based on session account type.

Implementation Details

Dual Wallet Initialization (lines 203-226)

// Ed25519 wallet for native Hedera operations
const hip820Wallet = HIP820Wallet.init({
  chainId: [hedera:${network}](http://_vscodecontentref_/0),
  accountId: ed25519AccountId,
  privateKey: ed25519PrivateKey,
})

// ECDSA wallet for EIP155-originated Hedera operations
const hip820WalletEcdsa = HIP820Wallet.init({
  chainId: [hedera:${network}](http://_vscodecontentref_/1),
  accountId: ecdsaAccountId,
  privateKey: ecdsaPrivateKey,
})

Code Quality Improvements

• Proper TypeScript null safety with non-null assertions
• Fixed type assertions for account objects (as const)
• Added comprehensive JSDoc documentation
• Updated useEffect dependencies to include new wallet instances

Testing

• ECDSA accounts (EIP155) can successfully call [hedera_signTransactions]
• Ed25519 accounts (native Hedera) continue to work correctly
• No TypeScript errors
• Proper signature validation for both account types

Breaking Changes
None - this is a bug fix ensuring correct behavior