12 signal functions covering staleness, repost patterns, salary transparency,
ATS blackhole detection, and enrichment signals. All pure functions — no LLM,
no network, no I/O. trust_score = 1 - sum(triggered weights), clamped to [0,1].
confidence reflects fraction of signals with available evidence.
Salary transparency enforced for CO/CA/NY/WA/IL/MA. ATS blackhole patterns:
Lever, Greenhouse, Workday, iCIMS, Taleo.
83 tests (models, all 12 signals individually, scorer). Bumps to v0.12.0.
