Sync AGENTS.md, CLAUDE.md, and .claude/rules from updated project_rules
templates: workplan-first session protocol, legacy terminology footnote,
and GET /workplans/ examples.
Implement Integration Definition validator CLI with schema and index checks,
pytest suite, and CI workflow. Register open-cmis-tck and issue-core-gitea in
the integration index.
Closes OPEN-WP-0003 and OPEN-WP-0004.