v0.8.3 — optional mink IK backend (proactive self-collision avoidance)

Skate Commander v0.8.3 — optional mink IK backend

An opt-in drag-IK backend built on mink's MuJoCo differential-IK QP, adding what the default pure-numpy DLS can't: proactive self-collision avoidance. The arm now glides to a safe standoff from the torso / legs / the other arm inside the solve, instead of the reactive capsule-guard reverting a blocked step (which could stall).

Measured on skt_v3: driving the hand 22 cm into the torso ends at a +14 mm body standoff instead of −90 mm of penetration.

Highlights

• --ik mink / SKATE_IK=mink — opt in; the numpy DLS stays the default and automatic fallback (a missing mink / qpsolvers dependency or a solver error can never break drag-IK).
• Same one-glide-step-per-tick contract; both arms; 6-DoF orientation and null-space comfort posture preserved; every non-target joint velocity-pinned.
• 3 new model-gated tests — 79 headless tests pass.

Non-breaking: default behaviour is unchanged.