Update ERC-7730: Remove embedded ABI; keys-as-schema (#1289)

* Document ABI sourcing guidance for ERC-7730

* Make display formats the single source of contract typing

* Add Kaan Uzdogan as ERC-7730 contributor

* Update ERCS/erc-7730.md

Co-authored-by: Kaan Uzdoğan <[email protected]>

* Remove the abi from ERC7730 json schema and examples

* savepoint

* savepoint

* Restore token formatting guidance and update contract paths

* Align examples with underscore-free parameter naming

* mention abi deprecation

* Validate format keys as function signatures

* Enforce format key syntax and clarify schema indexing

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Co-authored-by: Kaan Uzdoğan <[email protected]>

Author: llbartekll