docs: repair audited metadata anomalies

[yaacovcorcos]

Summary

• adds the four required metadata fields to the accepted 2026-08-22 T3 review
• replaces two free-form completion phrases with the allowed Historical status
• preserves each report's more precise completion statement as separate evidence

Boundaries

• no evidence content or architecture decision changed
• no Scient-agent repository inspection or change

Validation

• local Markdown links passed
• targeted diff reviewed
• git diff --check passed

[yaacovcorcos]

Hosted Actions cannot start because of the account billing/spending-limit error. Per docs/operations/github-operating-model.md, I ran the exact evidence-manifest workflow locally on the rebased PR head with Node v24.19.0: bootstrap safety passed; Gate 1.5 manifest passed; all 20 owned-source evidence tests passed; owned-source consistency passed; git diff --check passed; worktree remained clean.