DOC-AUTHORITY-ARCHIVE: establish one active documentation truth

[juv4uk]

Task-ID: DOC-AUTHORITY-ARCHIVE
Parent policy: juv4uk/ecosystem#5

Goal: prevent agents from treating stale architecture/design documents as current specification.

Required work:

• Add or refresh a root CURRENT.md that points only to the current semantic authority, contracts, active ADRs, active plans, and current test/oracle evidence.
• Create docs/archive/{superseded,completed-plans,experiments,historical} where applicable plus docs/archive/README.md stating archived material is non-normative.
• Audit all docs, dated reports, migration plans, PoCs and old architecture notes. Mark/move anything no longer current using history-preserving moves.
• Preserve provenance with Superseded-by: / Supersedes: links where useful.
• Update agent guidance so docs/archive/ can be read for history only and must never override Canon, semantic-registry, current contracts, active ADRs, or CURRENT.md.
• Add a lightweight guard if practical so active normative docs do not silently depend on archived material.
• Do not change runtime semantics as part of this cleanup.

Acceptance:

1. A new agent can find the current truth from one entry point.
2. Superseded docs cannot be mistaken for active requirements.
3. Historical evidence remains available.
4. Active docs have no unresolved contradictions with archived predecessors.
5. CI/docs checks remain green.