[DOCS] Setup hook should be added to doc

Question

### Documentation Type

Missing documentation (feature not documented)

### Documentation Location

https://code.claude.com/docs/en/plugins-reference#hooks

### Section/Topic

Hook

### Current Documentation

_No response_

### What's Wrong or Missing?

Missing newly added "Setup"

### Suggested Improvement

Should be added

### Impact

High - Prevents users from using a feature

### Additional Context

_No response_