- Created `src/transcript.rs` with concepts and traits for field operations.
- Defined a new `Limbable` trait for encoding translation between fields.
- Implemented `FieldWriter` and `FieldWritable` traits for respectively writing and producing field elements.
- Presented `FieldWritableExt` extension trait to accommodate different target field types.
- Added `FieldEncodingWriter` structure, a translating field writer.
- Integrated `smallvec` library with `const_generics` feature to implement it efficiently.
- Added tests for the `src/transcript.rs` module and its functionalities.

- Introduced a new `FieldEquippedWriter` struct in `transcript.rs` for efficient handling of "native" fields for digests.
- Implemented the ability to perform conversions from a writer, write field elements, and flush the writer using the new `FieldEquippedWriter` struct.
- Renamed the function `it_works` with `test_limbing_works` to improve test naming conventions.
- Implemented a new test, `test_keccak_works`, that verifies the Keccak256 hash of field elements implementation via `FieldEquippedWriter`.