[BACKLOG] Define explicit policy hierarchy and precedence model

[mark-e-deyoung]

Summary

Define an explicit policy hierarchy and precedence model so humans/agents can resolve wording differences consistently.

Problem

Policy statements are currently spread across README, CONTRIBUTING, SECURITY, and POLICY docs. Most are aligned, but there is no explicit precedence rule when wording diverges.

Proposal

Add a governance section documenting precedence, for example:

1. POLICY.md is normative.
2. CONTRIBUTING.md and SECURITY.md are normative in their domains.
3. README.md is informational summary; must not override normative policy.

Acceptance criteria

• Policy hierarchy and scope are documented.
• Docs cross-reference the hierarchy.
• Agents/humans can determine authoritative policy in one step.

Category

BACKLOG