[BUG] CAPABILITY accepts invalid arguments

[Aravinda-HWK]

Steps to Reproduce

Current command dispatch always routes CAPABILITY to the handler without argument validation.

Expected Behavior

RFC 3501 says CAPABILITY takes no arguments and invalid arguments should result in BAD.

Actual Behavior

The current handler does not check the argument count and always returns CAPABILITY plus tagged OK.

Relevant Logs / Screenshots

Result: a client sending something like A1 CAPABILITY EXTRA would likely get OK instead of BAD.

[Aravinda-HWK]

Hi @Deepak8858 ,
Thank you for starting contributing to our project.
Since you created a PR for this issue, our team would like to assign you to this issue. Our maintainers have put some comments in the PR. Please check them.