[FEATURE] display current values when no input given for --model

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Would be nice for claude --model to return the current model instead of giving an error about a missing parameter.

Proposed Solution

claude --model
Opus ✔ Opus 4.6 · Most capable for complex work

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_