Clarify administrator branch protection bypass

[arjitj2]

Closes #95.

Document the administrator bypass requested by the repository owner. Administrators may push directly to main or merge without first updating a PR branch from main. Non-admin contributors still require a PR, passing GitHub Actions verify check, and an up-to-date branch. The Allow force pushes and Allow deletions settings remain disabled.

Validation:

• Changed only the live enforce_admins setting from true to false through GitHub's branch-protection API. Readback and before/after comparison confirm every other protection field is unchanged. No additional rulesets apply.
• Documentation checker, 16 documentation tests, whitespace check, and plugin-tree equality pass.
• Only CONTRIBUTING.md changes. Previously passing package tests, typecheck, static checks and plugin validation still apply to these identical plugin bytes. CI repeats the required checks for this head.

No test push to main was needed. The setting is confirmed through GitHub's API and documented admin-bypass semantics.

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[Copilot]

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[arjitj2]

Independent maintenance review: PASS for 774ab7a against 928839a.

The guide describes the requested administrator bypass and names the unchanged Allow force pushes and Allow deletions settings. Saved API readback shows only enforce_admins changed from true to false. The earlier wording ambiguity is resolved. Only CONTRIBUTING.md changes; the packaged plugin tree remains identical. Documentation and whitespace checks pass in a clean detached checkout. No remaining findings.