Replacing all 4 context frames with identical measured snapshots gave the
planner zero velocity information, causing extremely slow motion that
degraded into jerky behavior. Now fills all 4 frames from planner trajectory
first (preserving continuity), then overrides only frame 0 with measured
state to ground the starting point in reality.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>