chore: strip config sections from repository-standards.md

[wphillipmoore]

Phase 3 of the standard-tooling.toml migration (vergil-project/vergil-tooling#363).

Strip the config sections (AI co-authors, Repository profile, Validation policy) from docs/repository-standards.md. These values now live in standard-tooling.toml and are read by the TOML-based config reader shipped in standard-tooling v1.4.6.

[wphillipmoore]

Completed in PR #468 (commit dc56221) — config sections stripped from repository-standards.md.