docs: v1.5.1 hosted Board release-qualification canary (#951)

[devin-ai-integration]

Summary

• Unmerged qualification artifact for the Code Mower v1.5.1 hosted Board lifecycle.
• Adds exactly one file, docs/archive/v151-hosted-board-canary.md, containing a generic qualification note.
• This draft PR must remain unmerged; it grants no merge or publication authority.

Closes #951

Validation

• python scripts/privacy_scan.py — passed
• git diff --check — clean

Risk / Rollback

• The change is an archive-only qualification artifact. Rollback is closing this draft PR and deleting its branch.

Data Or Secret Exposure

• This change does not add source, raw diffs, raw transcripts, raw provider output, tokens, provider-session links, or machine-specific paths to public artifacts.

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring

[github-actions]

Claude audit (merge-authority lane)

Head SHA: 6e7a978ab770ff16dbe8662d1c412eb2a27649ca
Verdict: PASS
Review details remain in the local audit artifact.
Publication workflow: .github/workflows/local-audit-publication.yml at e6fc0b147df3097e61f52a99b621d49a0e9aecc7

[github-actions]

Codex audit (merge-authority lane)

Head SHA: 6e7a978ab770ff16dbe8662d1c412eb2a27649ca
Verdict: PASS
Review details remain in the local audit artifact.
Publication workflow: .github/workflows/local-audit-publication.yml at e6fc0b147df3097e61f52a99b621d49a0e9aecc7

[jeffhuber]

Qualification is complete. Closing this draft without merge, as required; the exact-head audits, gate, provider exit, and Board evidence are recorded on #951.