Code review: stability risks and refinement targets

[Codex]

Need: assess current pathing simulator for stability/refinement gaps, not feature work.

• Runtime safety: Path edits while running reuse stale robot.t, leading to out-of-bounds access in updRobot; guard edits during run or reset robot.t/state on path changes.
• Speed/ETA accuracy: Curve/spline sampling uses fixed step counts while motion scales by LINE_RESOLUTION, so long curves run too fast and ETA drifts; sample curves by arc length or feed true segment lengths into the speed profile.
• Undo fidelity: Sidebar live edits update waypoints without snapshot, so undo/redo misses incremental changes; snapshot before live numeric edits (or debounce to change).

Example hotspot:

// scripts/animate.js
if (p0.type === 'delay' || p1.type === 'delay' || (p2 && p2.type === 'delay')) break;
// when path shrinks mid-run, index can point past pathArray, throwing here

Original prompt

Conduct a code review. Focus on refinement/stability of current features rather than feature additions.

Created from VS Code.