#7190 improvement(tools): prevent internal request self-hops

Summary

• forbid tool definitions from routing execution through same-origin Sim API endpoints
• document the in-process operation boundary across integration, tool, block, and trigger guidance
• remove the obsolete request.internal audit policy and replace it with self-hop regression coverage

Type of Change

• Improvement

Testing

• bun run lint
• bun run type-check
• bun run check:audits
• focused tool request and internal operation registry tests

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)