Lidar offset handling is now done in SangamIO (commit 64020cf), which
transforms lidar data to robot-center coordinates before streaming.
This simplifies VastuSLAM by removing hardware-specific configuration.
Also adds debug visualization support to SVG output:
- DebugMarker struct for custom markers with position, radius, color
- with_waypoints() for path waypoints (orange)
- with_frontiers() for frontier targets (green, labeled)
- with_markers() for arbitrary debug markers
- Dynamic legend sizing based on active entries
codetiger
3e78199709