Issue 118 must have length in for immutable array

[feO2x]

Closes #118

This pull request introduces the MustHaveLengthIn assertion for ImmutableArray<T> to the Light.GuardClauses library. The changes include adding production code for the assertion, creating corresponding unit tests, and documenting the implementation details. The main goal is to provide dedicated assertions for ImmutableArray<T> to avoid boxing and ensure optimal performance.

New Assertion Implementation:

• Code/Light.GuardClauses/Check.MustHaveLengthIn.cs: Added two overloads of the MustHaveLengthIn method for ImmutableArray<T>. One overload throws the default ArgumentOutOfRangeException, while the other allows custom exceptions via a delegate. Both methods check if the array's length falls within a specified Range<int> using the Length property.

• Code/Light.GuardClauses/ExceptionFactory/Throw.ImmutableArrayLengthNotInRange.cs: Introduced a helper method in the Throw class to create and throw an ArgumentOutOfRangeException when the ImmutableArray<T> length is outside the specified range.

Unit Tests:

• Code/Light.GuardClauses.Tests/CollectionAssertions/MustHaveLengthInTests.cs: Added comprehensive tests for the MustHaveLengthIn assertion, including cases for valid ranges, invalid ranges, custom exceptions, custom messages, and caller argument expression validation.

Documentation:

• Code/Plans/issue-118-must-have-length-in-for-immutable-array.md: Documented the implementation details and rationale for adding the MustHaveLengthIn assertion, along with tasks and notes for developers.

Minor Code Updates:

• Code/Light.GuardClauses/Check.MustHaveLengthIn.cs: Updated using directives to include System.Collections.Immutable for working with ImmutableArray<T>.

[Copilot]

Pull Request Overview

This PR implements the MustHaveLengthIn assertion for ImmutableArray<T> to avoid boxing issues when using generic collection assertions. The implementation provides dedicated methods that use the Length property for optimal performance and follows the established patterns in the Light.GuardClauses library.

• Adds two overloads of MustHaveLengthIn for ImmutableArray<T> (default exception and custom exception variants)
• Creates a dedicated exception factory method for immutable array length validation
• Provides comprehensive unit tests covering valid/invalid ranges, custom exceptions, and caller argument expression validation

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
Code/Plans/issue-118-must-have-length-in-for-immutable-array.md	Documentation outlining implementation requirements and tasks
Code/Light.GuardClauses/ExceptionFactory/Throw.ImmutableArrayLengthNotInRange.cs	New exception factory method for immutable array length validation
Code/Light.GuardClauses/Check.MustHaveLengthIn.cs	Implementation of two MustHaveLengthIn overloads for ImmutableArray<T>
Code/Light.GuardClauses.Tests/CollectionAssertions/MustHaveLengthInTests.cs	Comprehensive unit tests for the new assertion methods