v1.16.1

Fix: retired a dead staleness-detection check in skill-audit-edho-ferdian

A full audit run against all 34 skills found that the audit skill's own staleness detector had gone silently non-functional: it grepped for Adapted from <source>, fetched <date> provenance lines, but an earlier commit had already rewritten every such line away from that format while removing external-source attribution. The grep matched zero files — not because nothing was stale, but because the signal it looked for no longer existed anywhere in the corpus.

references/audit-checklist.md §1 now measures staleness against this ecosystem's own moving reference points instead of an external upstream: a skill's last substantive git-touch date is compared against the introduction dates of its own canonical cross-skill contracts (skill-authoring-edho-ferdian's §7/§8/§9 and future additions). The "never revisited" / "silently diverged" signals are kept, re-based on internal neighbors and a skill's own Provenance narrative instead of a fetch date.

The same audit confirmed 0 genuine broken cross-references and 0 new redundancy introduced by code-simplification-edho-ferdian (added in v1.16.0) — no other skill needed a change.

Full changelog: v1.16.0...v1.16.1