Add the 2026-04-14 and 2026-04-15 gate verification outputs, metric snapshots, trend reports, and design-drift daily reports.
This clears the remaining generated report changes from the worktree while preserving the validation evidence emitted during the refactor follow-up runs.
Add archive headers to historical review and report documents so they are explicitly downgraded to snapshot status.
Also add an archive index for the 2026-04-14 history batch to make current fact sources and traceability explicit.