Bug: pi-review.sh doesn't show untracked files in diff

When a coder creates a new file, pi-review.sh doesn't include it in the diff shown to the reviewer.

Problem

• git diff only shows changes to tracked files
• New files (untracked) don't appear in the diff
• Reviewer sees empty or incomplete diff
• May incorrectly REQUEST_CHANGES or not see the full picture

Solution

Include untracked files in the diff output. Options: 1. Stage files before diffing: git add -N . then git diff 2. Separately show untracked files: git ls-files --others --exclude-standard + cat each 3. Use git diff for tracked + separate section for new files

Recommendation

Option 3 - show tracked file diffs normally, then add a section like:

## New Files
=== path/to/new/file.sh ===
<full contents>

This gives the reviewer full context without modifying git state.