Nonce-Specific Deployment Task for Cross-Chain Address Matching

[Maar-io]

This PR adds a Hardhat task deployAtNonce that deploys an upgradeable AstarToken contract at a specific nonce to ensure address consistency across multiple chains. The script:

• Deploys the implementation contract at nonce N-1
• Deploys the proxy contract precisely at nonce N (default 15)
• Fast-forwards transactions if needed to reach the target nonce
• Verifies the proxy contract address matches the expected address from Soneium network
• Includes optional contract verification on block explorers

Why This Approach
This approach was necessary because the original Astar token on Soneium was deployed using the standard CREATE opcode (not CREATE2), and specifically at nonce 15 of the deployer account. Since Ethereum contract addresses are deterministically generated from keccak256(rlp([deployer_address, deployer_nonce])), the only way to achieve the same contract address on Optimism is to:

• Use the identical deployer address
• Ensure deployment happens at exactly the same nonce (15)

This ensures token address consistency across chains, which is critical for cross-chain bridging protocols and provides a seamless user experience.

[gtg7784]

can we use this env-enc ? any reason for removing this?

[Maar-io]

yes, reverted