Standardize current Markdown naming and structure checks

Summary

Standardized the current documentation naming convention around uppercase hyphenated Markdown filenames and added a current-doc structure audit.

This item intentionally leaves historical provenance filenames in place unless they must be touched for active policy-link correctness.

Completed Work

• Renamed the policy entrypoints to WORKSPACE-POLICY.md and DOCS-POLICY.md.
• Updated workspace and repo references to the new policy path.
• Added scripts/docs-structure-check.py for current-doc filename, heading, navigation, and wide-table checks.
• Documented the browser-readable table guidance in DOCS-POLICY.md.
• Added missing navigation entries for CI-BASELINE.md and REST-API-ADAPTERS.md.

Validation

• git diff --check
• python scripts\docs-item-taxonomy-check.py
• python scripts\docs-structure-check.py
• python scripts\github-roadmap-check.py
• python scripts\github-roadmap-check.py --github

Implementation is recorded by the tooling commit that adds this item.