feat: Enhance MultiSigContractV2 storage with transaction tracking mappings and Natspec

[SynnekOG]

PR Description

This PR introduces several important storage improvements to MultiSigContractV2 to better track transactions, their signers, and signatures. These changes are aimed at improving transparency, auditability, and developer understanding of the contract.

Changes:

• Add Storage Natspec Header

  • Provides clear documentation for the storage section of the contract.

• Add transactions Mapping

  • mapping(uint256 => TransactionData) private transactions;
  • Stores all transaction data keyed by transaction ID.

• Add hasSignedTransaction Mapping

  • mapping(uint256 => mapping(address => bool)) public hasSignedTransaction;
  • Tracks whether a specific address has signed a given transaction.

• Add transactionSigners Mapping

  • mapping(uint256 => address[]) public transactionSigners;
  • Keeps a record of all addresses that have signed a particular transaction.

• Add transactionSignatures Mapping

  • mapping(uint256 => address[]) public transactionSignatures;
  • Stores the actual signatures associated with each transaction ID.

• Code Formatting

  • Applied forge fmt for consistent styling and readability.

Motivation:

These updates are foundational for enabling a more robust multi-signature workflow. By explicitly tracking transaction signers and signatures, we ensure:

• Better auditing and verification of transaction approvals.
• Clearer visibility into the state of each transaction.
• Improved maintainability and clarity for future developers.

Files Updated:

• src/MultiSigContractV2.sol – Added new mappings and Natspec header, applied formatting.

Notes:

• No functional logic was changed; these are purely storage and documentation improvements.