Ether support

[mriynyk]

Issue

This PR introduces comprehensive native Ether support across the DigitalOriginal protocol, alongside significant architectural refactoring to unify currency handling.

Summary:

• Native Ether Support:
  • Developed CurrencyTransfers.sol to provide a unified interface for both Ether and ERC-20 transactions.
  • Implemented a robust "send-and-wrap" fallback mechanism: if a direct Ether transfer fails (e.g., due to recipient gas limits), the contract automatically wraps the Ether into WETH and completes the transfer.
  • Updated ArtToken, AuctionHouse, and Market to support native Ether for minting, bidding, and secondary sales.
• Architectural Refactoring:
  • Centralized value movement logic within the CurrencyTransfers abstract contract, replacing manual SafeERC20 calls and deprecated utilities like SafeERC20BulkTransfer.
• Infrastructure & Testing:
  • Added WrappedEther mock and IWrappedEther interface to facilitate rigorous testing of Ether/WETH fallback logic.
  • Updated the entire test suite and deployment tasks to accommodate native Ether and Wrapped Ether usage.
  • Standardized project configuration (.nvmrc, .npmrc, updated linting/formatting rules) and enhanced the CI pipeline.