[Extension] 20. Archive chatbot share-link evidence

[code259]

Goal

Preserve a small number of public chatbot share pages with provenance and retention metadata.

Why this matters

Share links are stronger evidence than screenshots but may disappear. Archiving directly addresses authenticity and evidence-loss risks.

Work

• Fetch supported public share URLs safely.
• Store content, capture time, source URL, content hash, and retention date.
• Reject unsupported schemes, private addresses, and oversized responses.
• Keep artifacts out of Git and behind access controls.
• Validate with two public examples if available.

Done when

A supported link can be archived and later verified by hash without exposing the artifact publicly.

Priority: Optional; choose this or deeper classifier work if time is tight.