Add ChangeSubclass method to CBaseModelEntity

[agasking1337]

Introduces the ChangeSubclass method to both the CBaseModelEntity interface and its implementation. This method allows changing the subclass by accepting an item definition index.

Description

Introduce a dedicated ChangeSubclass(ushort itemDefinitionIndex) method (and interface entry) that just forwards to AcceptInput("ChangeSubclass", itemDefinitionIndex.ToString()). This gives callers a clearer and type‑safe way to change an item’s subclass without manually invoking AcceptInput.

Type of Change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code refactoring (no functional changes)
• Performance improvement
• Test coverage improvement
• Build/CI improvement

Related Issues

Fixes #(issue number)
Closes #(issue number)
Related to #(issue number)

Changes Made

• Native changes (C++)
• Managed Changes (C#)
• API additions/modifications
• Memory management improvements
• Network handling changes
• SDK updates
• Build system changes

Detailed Changes

List the specific changes made:

Testing

Yes

Test Environment

Windows 11

• OS: (e.g., Windows 11, Ubuntu 22.04)
• Game: (e.g., Counter-Strike 2)
  cs2

Test Cases

Describe the test cases you've run:

1. Granting player weapons like baionet knife

Breaking Changes

List any breaking changes and migration steps:

Performance Impact

• No performance impact
• Positive performance impact
• Negative performance impact (explain below)
• Performance impact unknown

Details:

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Screenshots/Videos (if applicable)

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Additional Notes

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For Maintainers

• Code review completed
• Tests pass
• Ready to merge

[skuzzis]

Thanks for the PR <3