fix: Add mkdir -p to auto-approve bash permissions

## Problem
Getting prompted for `mkdir -p` permission when creating worktree directories. This is a safe, idempotent operation.

## Exact Prompt
```
Bash command
mkdir -p ~/ppv/pillars/dotfiles/worktrees
Create worktrees directory

Do you want to proceed?
```

## Solution
We already have `"Bash(mkdir:*)"` in permissions, but need to check if it's working correctly or if we need a more specific pattern.

## Note
`mkdir -p` is safe because:
- Creates parent directories if needed
- No error if directory exists
- Read-only in nature (just creates structure)

Related: #593, #600, #603 (permissions work)
Principle: tracer-bullets

Start by locating the permission configuration containing the existing "Bash(mkdir:*)" rule and reproduce the `mkdir -p` prompt. Verify how the pattern is matched and adjust the permission entry if needed; done means the shown worktree-directory command no longer prompts for approval.

Written by the indexing model from the issue text.