#7207 improvement(tools): retire direct execution

Summary

• remove the retired directExecution runtime and type surface
• migrate all affected tools to registered semantic operations under lib/internal/<family>/
• preserve trusted background execution authority and add CI and authoring guidance to prevent regressions

Type of Change

• Improvement

Testing

• bun run lint
• bun run check:audits
• bun run type-check
• 22 changed test files, 653 tests passed

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)