v0.1.2 -- live visualization + intended-motion preview

New optional [viz] extra: a browser-based live robot mirror + intended-motion preview, for safety and debugging. 'flexiv-control viz --connect ' mirrors a running arm from any machine on the LAN (read-only, never takes the lease); RobotViz.preview_chunk renders each chunk's TRUE per-tick command stream (the executor's own resolution + caps + interpolation, so time-stretching is visible) as a time-colored path with waypoint knots, gripper open/close glyphs, terminal pose, and an animated ghost TCP -- plus the live workspace box from the active safety profile, a measured TCP trail, a wrench/status HUD, a stale-preview guard, an optional browser Approve/Reject gate for per-chunk confirmation, and a commanded-vs-measured overlay after execution. pip install 'flexiv-control[viz]'. See docs/visualization.md.