Introduce a new `DocumentDetailsDto` record to encapsulate shared document metadata and elements without binary payload. Refactor `DocumentDto` to inherit from `DocumentDetailsDto`, eliminating redundant properties and improving code reuse.
Convert `DocumentDto` from a class to a record for immutability. Add a parameterized constructor to `DocumentDto` for initializing binary data alongside metadata. Update `ByteData` to use the `init` accessor.
These changes enhance maintainability, reduce duplication, and enforce immutability by leveraging C# records and inheritance.
