[WIP] Recipe model_dump fixes

[rahul-tuli]

This PR builds on top of #1328 and reintroduces those changes which were reverted in #1378 due to failing base tests. It addresses issue #1319 by refactoring the Recipe class, particularly improving its serialization capabilities to ensure proper round-trip consistency.

Key Changes

Recipe Class Structure Improvements

• Reorganized class field declarations to the top of the class for better code organization and readability
• Fixed field type annotations, making version and metadata properly Optional
• Replaced the deprecated dict() method with the Pydantic v2 compatible model_dump() method
• Completely rewrote the serialization logic to produce cleaner, more consistent YAML output

Serialization Enhancements

• Implemented a new model_dump() method that properly formats recipe data for serialization
• Removed the redundant _get_yaml_dict() helper method by integrating its functionality into model_dump()
• Fixed argument handling during recipe creation to prevent nesting issues
• Improved stage grouping and naming conventions for better serialization consistency

Test Improvements

• Restructured tests into organized test classes with clear purposes
• Added testing for serialization and deserialization workflows
• Introduced new test cases for file-based serialization
• Created helper methods for comparing recipe modifiers to improve test readability
• Added a new valid recipe test case to validate the enhanced serialization format