Add curved trajectory support using Adaptive Pure Pursuit

[gdoffe]

Context

The current motion control chains (QUADPID, QUADPID_TRACKER) use PoseStraightFilter which enforces straight-line segments between waypoints (rotate → translate → rotate state machine). This makes curved trajectories impossible without stopping and rotating at each waypoint.

Goal

Add an Adaptive Pure Pursuit controller chain that generates continuous steering commands by tracking a lookahead point on the path. This enables smooth curved path following without the rotate-stop-translate pattern.

Key features

• Adaptive lookahead distance based on current speed
• Curvature-based speed limiting for safe cornering
• Forward and backward motion support
• Initial rotation phase for large heading errors
• Path interpolation between waypoints

Related

• Allow to pass a list of points through canpb #211 (multi-waypoint path navigation)
• PR 211 Multi-waypoint path navigation and Adaptive Pure Pursuit #230 (merged, included early pure pursuit work that was later removed)