Task 3.1 (Req 4.1-4.4).
- semantic/loo.py: every scorable pair is held out once; a temporary
store is seeded from the other seeded/reviewed pairs (advisory and
title pairs are scored as targets, never teach; known_limit skipped);
both excerpts are searched for variants and scored with the pair rules
(detected inside the labeled function naming the labeled mechanism or
sink; silent when the fixed side yields no hit); found_by and leaked_by
name the records and the pairs that taught them; metrics per slice,
profile and mechanism; score_pair_with_store is shared with the lever.
- cli: `pairs --slice S --loo [--loo-out P]` writes loo.json; never a gate.
- First measurement: vibe-py 35 pairs, 11 detected, 21 silent, Youden
-0.086, 16 teaching pairs.
Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG
