Standard 1.5.1: Add actionable review correction protocol

[artyomboyko]

Summary

Add a proportionate reviewer-to-agent correction handoff for blocking Pull Request findings and publish Agent Handoff Standard 1.5.1.

A blocking finding carries a stable ID, evidence, violated contract, cause confidence, required outcome, invariants, scope guard, applicable verification, and observable acceptance criteria. Implementation guidance remains non-binding for equivalent safe corrections. Agent-reported addressed remains distinct from reviewer-confirmed verified.

Related issue

Closes #18

Agent handoff

• Agent ID: review-lynx-5a1c
• Run ID: 20260727-issue-18-5a1c
• Work claim exists: yes
• Stage or final result comment exists: yes

Change type

• Bug fix
• Standard change
• Documentation
• Template change
• Refactoring
• Research
• Other

Checks

• Related Issue or PR is linked.
• Required files exist.
• Links work.
• Forms are valid when changed.
• Required stage or final result comment exists.
• Smoke tests were run or reason is documented.
• Primary outcome, smallest acceptance proof, and execution envelope are recorded; supporting work did not become an independent stage, handoff, completion target, or approval gate without crossing an explicit boundary.
• Blocking review findings, when present, contain sufficient correction contracts; agent-reported addressed findings map to changes and evidence, and reviewer verification remains separate.
• Security and evidence work did not block acceptance or expand scope without a verified High/Critical current-scope risk or an exactly cited mandatory requirement; other items remain non-blocking.
• Mandatory containerization decision was confirmed when relevant, or not applicable.
• Changed Compose configuration was rendered and checked, or reason and risk are documented.
• Automated GUI tests avoid position-dependent selectors, or manual/supervised checks are documented.

State updates

• ai/PROJECT_STATE.md updated, or not needed.
• ai/DECISIONS.md updated, or not needed.
• Handoff file added, or not needed.
• ai/handoffs/INDEX.md updated, or not needed.

Validation

• python3 scripts/check_agent_handoff.py — passed.
• Python syntax compilation for scripts/check_agent_handoff.py — passed.
• Negative checker test without ai/REVIEW_PROTOCOL.md — failed as expected.
• Relative Markdown link validation — passed.
• git diff --check — passed.
• Remote/local 24-file content comparison — exact match.
• GitHub Actions run 30266060075 — success on head 99f6b90644c1fdc53466906be353c6be0aa68b18.

Risks

• No product code, container layout, security baseline, existing tags, or repository settings change.
• The structural checker verifies required protocol fields but does not attempt semantic review-quality scoring.

Next steps

Squash-merge the verified PR, then publish tag and GitHub Release v1.5.1 from the merge commit.