v2.5.0 — verification and currency

The verification-and-currency release. Highlights:

• Qualified gates: eight backtest gates run on every commit and in CI — each one proven against seeded defects and clean controls before it may clear work, with recall and false-alarm rates recorded in quality_reports/qualification/LEDGER.md. An unqualified check is not weak evidence; it is none.
• A machine-checked finding contract for all review fan-outs (finding-schema.json + validator), with refute-biased verification before anything reaches a judge.
• The external-oracle process: an independent frontier-model referee run, with every finding adjudicated against the text — never ingested on trust. This release itself went through one.
• GitHub as memory: issues as defect memory, quality_reports/ as work memory, MEMORY.md as lesson memory; repo hygiene enforced by a checker ("scratch must not become main").
• An eval harness with a behavioral manipulation check (each arm must prove skill access), variance gating, and honest recording of what could and could not be measured.
• A full currency pass over the guide, README, landing page, and reference library — model versions from a single dated source of truth, content-fingerprint render stamping, and staleness checks with expiry dates.
• New guide material: the adoption ladder, enforcement-contract matrix, pattern pathways, a red-then-green first-five-minutes demo, and a git survival kit.

Complete record with the full adjudication history: CHANGELOG.md.