git:20260925.9fccf88 to git:20261017.81c04e9

+ - **The noise trim runs on relevance, and decay is a switch, not a curve.** Both engines trim at 10% of the top RRF × salience score *before* any age weighting. Run after decay, as the API did until 2026-10-16, the trim cut old records for their age: 55 of 240 known items were absent from the pool, not merely ranked low. The CLI had no trim, so the engines also disagreed about the pool. Fusion is rank-based: rank 1 scores 1/61, rank 10 scores 1/70, and a rank-1 partial match in another ladder also scores 1/61. An old known item therefore survives the page only if its age factor stays within a few percent of 1. Measured on 204k events (240 known items, 40 recency cases, semantic off), known-item S@10 by age <7d/7-30d/30-90d/90d+ was exp λ=0.001 0.98/0.85/0.62/0.15; power-law t^-0.5 0.98/0.77/0.62/0.30; ACT-R base-level d=0.05 0.80/0.53/0.60/0.72, trading the week for the archive. So when ≤ `CARTOGRAPHER_DECAY_LOOKUP_MAX` (10) candidates hold every query token, those candidates skip decay: 0.98/1.00/0.98/1.00 on the API, with recency unchanged. On the CLI, measured on paired cases, past 90 days went 0.23 → 1.00. Everything else decays as before. "Holds every token" is presence-only (`full` on `scoreBM25` results, column 10 of `bm25-search.awk`), so the engines agree although their idf differs. `tests/unit/age-curve-gate.test.js` proves its fixture reproduces the loss before gating, and `scripts/age-curve.js` runs the same curve on the live corpus. Change λ, the trim, salience or the exemption only with both. A different browse curve also needs the `demo/truth` set, because both gate metrics reward steeper decay (docs/SCORING.md).