Align maintainer PR workflows with shared code-change and security considerations

## Outcome

Maintainer PR workflows consume the same engineering considerations used during planning and implementation while retaining only their stage-specific selection, comparison, gate, and decision mechanics.

## Dependencies

- #8360
- #8361
- #8362
- #8363

## Scope

- Narrow nemoclaw-maintainer-day routing to explicit maintainer-loop and release-queue requests so it cannot capture generic issue implementation.
- Make security review a procedural wrapper around the canonical security rubric.
- Make PR comparison use canonical merge evidence plus shared code-change and security considerations; Advisor output remains review evidence rather than a score or merge authority.
- Keep merge eligibility in executable gates and current workflows instead of copied check-name or E2E inventories.
- Fold general sequencing into issue planning, general implementation and test-gap repair into the implementation or CI workflow, and security sweeping into security review.
- Fold PR selection into morning or day orchestration and related-work discovery into planning, implementation, and independent diff review where those moments own the evidence.
- Remove stale path inventories and redundant specialist routing after their owning workflows cover the behavior.

## Acceptance criteria

- [ ] Maintainer orchestration composes canonical workflows instead of copying their rules.
- [ ] Generic issue planning and implementation never trigger maintainer-day.
- [ ] Security and code-change considerations have the same meanings before and after a PR opens.
- [ ] Advisor findings are independently verified and cannot authorize approval or merge.
- [ ] Current code and workflows own risky paths, required checks, selectors, and E2E inventories.
- [ ] Each changed maintainer skill includes positive, negative, ambiguous, and clean-context routing tests.

Start by reading dependencies #8360–#8363 and the current maintainer workflows, then trace nemoclaw-maintainer-day routing and the changed maintainer skills. Run or add the routing tests covering positive, negative, ambiguous, and clean contexts. Done means orchestration composes canonical workflows, generic issues do not trigger maintainer-day, and Advisor findings cannot authorize approval or merge.

Written by the indexing model from the issue text.