Implements ROS2 geofence enforcer for SaltyBot with:
- Loads polygon geofence from params (list of x/y vertices)
- Subscribes to /odom for real-time robot position
- Point-in-polygon ray casting algorithm for boundary checking
- Publishes Bool on /saltybot/geofence_breach on boundary violation
- Optional enforcement flag for cmd_vel zeroing
- Configurable safety margin
- Includes 20+ unit tests for geometry and breach detection
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
