After visual verification 2026-05-18 (turn lag, coast-and-settle,
slope-tilt, jump tracking with contact-plane projection all working),
make the retail chase camera the default. Legacy ChaseCamera stays
available via the DebugPanel toggle (ACDREAM_RETAIL_CHASE=0 or the
checkbox) pending a follow-up deletion commit.
Env var polarity now matches AlignToSlope: default-on if unset, off
only when explicitly "0".
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>