Add whitelist mode for command filtering

Feature Request: Whitelist Mode for Command Filtering

Currently, RTK only supports blacklist-style filtering via exclude_commands in the config. I would like to request a whitelist mode:

• Only commands explicitly listed in include_commands are filtered and rewritten by RTK.
• All other commands should be passed through unchanged.
• Example syntax:

[hooks]
include_commands = ["git status", "cargo build"]

Use Case: This type of control lets users opt-in with a safe set of verified commands, reducing risk from unknown scenarios and making adoption in stable workflows much safer. This would be mutually exclusive with exclude_commands.

Thank you!