docs(openspec): archive the stop-advisory-ci-schedules change

[Drswith]

Summary

Archive stop-advisory-ci-schedules after its implementation PR (#681) merged, syncing the accepted code-quality-tooling and agent-canary-validation deltas into openspec/specs/.

Main specs now require manual-dispatch-only coverage for advisory Sandbox Tests and full Agent Canaries, and no longer require standing Tuesday/Saturday schedules. PR canaries remain unchanged.

restore-managed-update-and-resume-releases remains the only active change; it is an umbrella change and stays active by design.

Linked Artifacts

• OpenSpec: stop-advisory-ci-schedules

Validation

• bun run openspec:validate
• bun run memory:check
• bun run lint
• bun run format:check
• bun run typecheck

bun run test is not applicable: this PR changes only openspec/ Markdown.

Release Intent

• Release: not applicable - OpenSpec archive closure only

Release Summary

• Not applicable - OpenSpec archive closure does not produce a release entry.

Docs Updated

• openspec/...

Scope Check

• I did not add a new ad hoc root-level Markdown file.
• I updated the relevant issue, ADR, spec, runbook, or captured the missing doc work as follow-up.
• I did not silently expand project scope without recording it explicitly.

Closure Check

• Working tree was clean before archive closure started.
• Branch was pushed and this PR is the active delivery artifact.
• OpenSpec change is already archived or queued for agent-driven archive closure.
• Release is not applicable, delegated to release automation, or verified.

Notes

Generated by bun run openspec:archive-closure -- stop-advisory-ci-schedules --apply-specs. The generated openspec/changes/archive/2026-09-02-.../ directory was removed rather than committed, matching #680 and every archive PR since 2026-08-16.