Initial commit with Boolean and Enum implementation

[abhishek130904]

Summary

This PR adds support for Boolean and Enum types in LowType.

Changes

Boolean

• Introduced a dedicated Boolean type
• Validates only true and false values
• Replaces factory-based implementation

Enum

• Added Enum[val1, val2, ...] type constructor
• Implemented Enum::Definition with match? validation
• Supports union types (e.g. Enum[:a, :b] | nil)

Core Integration

• Updated TypeQuery to recognize Enum::Definition
• Extended TypeExpression to support non-Class types with match?

Tests

• Added unit tests for Boolean and Enum
• Added feature tests
• All existing tests pass (140 examples, 0 failures)

Motivation

• Improves readability (Boolean vs TrueClass | FalseClass)
• Adds support for constrained value sets
• Aligns with planned features in project roadmap

Notes

• Maintains backward compatibility
• Integrates cleanly with existing type system

[maedi]

Thank you for this PR. There are a few people interested in this issue via GSoC and it will take a while to sort through the solutions and apply the most suitable one. I have a few proposals via GSoC, including a strong proposal, so I will have to get all of the solutions in my head at once somehow :) Your contribution is appreciated and I will read it and provide feedback