F7 follow-up: role-separation PR policy enforcement

[ArchonVII]

Summary

Follow-up from ArchonVII/.github PR #20 / issue #14.

pr-policy.yml should encode the lane-specific role-separation decision:

• Same-account author/merger identity is a soft warning by default, not a universal hard block.
• Agent-managed code/config/policy PRs touching protected paths should get a scoped hard block unless independent Release-Admiral closure is represented by the PR metadata/body.
• Owner Maintenance Lane is direct-commit-only and should not be modeled as a PR-path exemption.
• Dependabot auto-merge remains the documented exception.

Acceptance

• PR policy can detect same-account author/merger or equivalent self-close risk and report it as warning by default.
• Protected path/lane rules can opt into a hard failure for agent-managed code/config/policy PRs.
• Tests cover soft-warning default and scoped hard-block behavior.
• README/examples document the new inputs and the owner-maintenance non-exemption.

Source

• F7: Codify Open-Admiral / Project-Lieutenant / Release-Admiral / Issue-Admiral role separation .github#14
• docs(profile): codify role separation policy .github#20