docs: clarify canonical LocalSetup repository name

[CruxExperts]

Summary

• State CruxExperts/LocalSetup as the canonical GitHub repository name in root policy.
• Preserve existing repository URL paths and technical compatibility identifiers.
• Keep the release record and README current for the branding work and naming clarification since published v5.6.2.

Validation

• Publish preflight: ready for 5.7.1 with no pending changes.
• Release documentation check: passed with zero findings.
• Documentation alignment CI check: passed with zero findings.
• Strict branding validation: passed with zero findings across 2,158 files.
• Documentation generators reran without drift; git diff --check passed.

[chatgpt-codex-connector]

Codex usage limits have been reached for code reviews. Please check with the admins of this repo to increase the limits by adding credits.
Repo admins can enable using credits for code reviews in their settings.