Publish lossless applied-action evidence for Qualia

[superposition]

Summary

Expose continuous, completed, post-safety differential-drive action intervals from Leash so Qualia can record real JEPA supervision without reconstructing commands from UI requests.

Deliverable

• Leash-owned producer epoch and monotonic action sequence.
• Completed intervals carrying requested, clamped, and applied wheel values, speed scale, safety flags, validity, and deadman/collision provenance.
• Bounded append-only HTTP history with explicit overrun behavior.
• Periodic zero-action heartbeats so zero-motion evidence has continuous temporal coverage.
• Tests for clamping, collision/deadman stops, restart epochs, pagination, and no skipped intervals.

Safety

Leash remains the sole motor and safety authority. Reading/publishing evidence never issues motion. No physical motion is authorized by this issue.

Acceptance

Qualia drains every interval without gaps, MCAP replay preserves it, and a zero-motion preflight proves both robots report continuous authoritative zeros.

[superposition]

Implemented in draft PR #191: lossless 100 ms post-safety action intervals, explicit overrun, and read-only pagination. Full tests, strict Clippy, and the physical feature build pass. Deployment validation on Guard/Pinkie is the next gate.