Update ERC-7730: Add command registries, nested encoding, and packed multicall

[muhammadaus]

Adds support for complex protocol patterns not covered by the existing calldata format:

• Command-Based Protocols (e.g., Uniswap Universal Router): commandRegistries
  for mapping command bytes to ABI specs, nestedEncoding field, and composite
  intents
• Packed Bytes Multicall (e.g., Safe MultiSend): parsing.multicallStructure
  for custom byte layouts and multicallBatch format

[eip-review-bot]

File ERCS/erc-7730.md

Requires 1 more reviewers from @arein, @arikg, @kuzdogan, @lcastillo-ledger, @llbartekll, @paoun-ledger