Preserve reviewed snapshots during refresh and validate quote matches

[benvinegar]

Problem

refresh --write updates measurements and the pinned commit, then syncs files, before the editorial analysis has been reread. This can leave existing analysis and quotes describing an older revision. The offline validator checks schema and vendored-file consistency but does not verify quote matches.

The review checked all 204 current editorial quotes against stored source after whitespace normalization and found no mismatches. This issue closes a workflow gap rather than reporting currently broken quotes.

Proposed change

Stage proposed source and measurement updates separately from the published, reviewed snapshot. Promote source and analysis together after review. Make quote matching part of offline validation.

Acceptance criteria

• Refresh discovers changes without advancing the published analysis snapshot before review.
• Failed or incomplete refreshes preserve the last valid snapshot.
• Measurements and source bytes come from the same resolved commit; a commit lookup failure cannot pair new measurements with an old revision.
• Validation checks every quote against its designated primary or supporting source and reports actionable failures.
• Validation permits the established whitespace normalization while preserving original rendered source lines and wording.
• Document promotion/review steps and test failure paths; run lint and typecheck.

Relevant files: scripts/refresh-agents-md.ts, scripts/validate-agents-md.ts, lib/agents-md.ts, docs/corpus.md.