[Feature Request] Add custom advisory text support to PermissionRequest hooks

Question

**Bug Description**
- What: Ability for PermissionRequest hooks to inject custom advisory text    
  (e.g., risk classification) into the Allow/Deny confirmation dialog
  - Why: systemMessage is documented but doesn't display in the permission      
  prompt UI, making it impossible to add contextual information at the decision 
  point
  - Use case: Automated risk classification (LOW/MEDIUM/HIGH) shown alongside   
  each permission prompt

**Environment Info**
- Platform: darwin
- Terminal: Ap