Add comprehensive tests for isPrivateIP() and getUserIP() functions.
These tests currently fail as the functions are not yet implemented.
Tests cover:
- isPrivateIP: loopback, private ranges (10/172/192), AWS metadata, public IPs
- getUserIP: REMOTE_ADDR fallback, X-Forwarded-For parsing and trimming
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
