Fix the regression introduced by the weighted Laya signal (#16):
rebuild now merges exact fingerprints in every engine mode after
evaluating hard blockers, compares candidates against all variants
of a group, falls back to deterministic scoring when Laya is
unavailable, and reports transaction errors safely. Non-regression
tests cover the Laya-mode rebuild path; verified against a real
catalog copy (39,341 streams rebuilt successfully).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Introduce a liveGroupingScoring engine that combines existing
membership signals (normalized name, brand, number, metadata tokens,
language, category/source when relevant) with a bounded Laya
contribution: Laya raises or lowers confidence instead of acting as
a final judge, with guard-rails against obvious contradictions.
Sanitize Laya batch identity inputs in layaService and wire the
weighted scoring into the live projection service. Weights are not
exposed in the Nodecast UI. Cover signal combination, bounds and
contradiction guard-rails with tests.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
