Eviction cleanup() closed the llama ctx / killed the dinov2 subprocess
while another thread was mid-encode (embeddings hold no pool ref, so
_is_key_busy saw idle) — use-after-free segfaults that crash-looped the
radeon engine. cleanup() now takes the same per-model lock the embed
paths hold, so it waits for the in-flight call.

Engines card: the loaded-models hover now lists each model with its
measured VRAM footprint and, separately, the host-RAM slice when
CPU-offloading. Plumbed engine-state loaded_info → supervisor →
registry → engines_list → tooltip.

dinov2cpp: build the quantize tool too (dinov2-large-Q8_0 is lossless
at cos 0.9973 and drops 612→329 MB).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014S8VtAvG499SsCbeESRK7V