[Feature]: Add --lint support

[Malcolmnixon]

Problem Statement

ReviewMark should have a lint option to lint the configuration file and report issues.

Proposed Solution

Add a --lint command which reads the configuration file and checks if it's valid. The result should be written using the Context.WriteLine or Context.WriteError so lint-failures also result in a non-zero exit code.

Alternatives Considered

No response

Usage Examples

Benefits

This provides the ability to check the configuration file is valid.

Priority

Medium - Would improve my workflow

Willingness to Contribute

Yes, I can submit a pull request

Additional Context

Lint errors should be clear about the cause and location so that the issues can be easily fixed.

Checklist

• I have searched existing issues to ensure this is not a duplicate
• I have provided a clear description of the feature
• I have explained why this feature would be useful