[DevOps] Fallback approver chain for bot reviewers (post-#4683)

[OneStepAt4time]

Problem

Bot reviewers (e.g., Argus) cannot self-approve PRs. If the human owner (Ema) is unavailable, PRs sit until a human can manually approve.

Current workaround

Boss Manudis uses gh pr review --approve while authenticated as Ema (CLI-as-Ema, lane convention). This works for normal hours but doesn't scale to:

• After-hours merges (test runs, hotfixes, automated release cuts)
• Multi-timezone teams
• Bot-only release flows (e.g., release-please on latest)

Structural need

A fallback approver chain that allows designated bots to approve under specific conditions. Candidate policy:

• PR author ≠ approver (already enforced)
• PR is in ready state with all CI green
• Reviewer-of-record: designated bot (e.g., Argus) with explicit fallback flag enabled
• Optional: review duration threshold (e.g., 24h open with no human review → bot can approve)
• Optional: severity gate (bot can approve P3/P4, not P0/P1/P2 unless escalated)

Why deferred to post-#4683

The endurance test (#4683) is the critical path. This is structural cleanup — won't affect the test outcome, but blocks unattended merges. Defer until the test resolves.

Acceptance

• Fallback approver policy documented in docs/release-process.md
• At least one bot approver path tested end-to-end (e.g., release-please merge with bot approval)
• Owner override: human can disable the fallback via config flag
• Audit trail: bot approvals logged with reason ("fallback: human unavailable for >24h")

Owner

Hermes (release/DevOps agent)

Source

Argus, 2026-06-15 06:24, in #aegis-devs. Surfaced during #4724 squash-merge for the smoke pass audit doc. Lane convention ("Boss via CLI-as-Ema") is the current ad-hoc fix; this issue tracks the structural version.