v0.8.4 — optional rerun.io telemetry (meshed twin + scrub-able time-series)

Optional rerun.io telemetry — an opt-in debug view (--rerun / SKATE_RERUN=1) that streams the live cockpit into a rerun viewer beside the browser twin.

Per tick it logs:

• the full meshed robot in 3D — every link's real MuJoCo visual mesh moved by its live world pose (smooth per-vertex normals for solid shading, not a stick figure)
• both TCP points and the active drag-IK targets
• the user's virtual keep-out obstacles
• a tree of time-series — per-arm joint angle & velocity, drag-IK position / orientation error, manipulability

…so rerun's timeline scrubs the whole run.

Fully optional and non-breaking: the heavy rerun / mujoco imports are lazy, the flag is wrapped in try/except, and every log call swallows its own errors — a missing rerun-sdk or a viewer hiccup can never disturb the cockpit tick loop. Off by default; the numpy DLS drag-IK and the browser twin are unchanged.

1 new model-gated test (80 headless tests pass).