fix: enforce strict schema for debug workflow tester

[haosenwang1018]

Summary

• enable strictSchema: true for the tester agent in debug-workflow
• add a template resolver regression test that locks this behavior in

Related Issues

Fixes #458

Changes Made

• update cluster-templates/base-templates/debug-workflow.json so the tester keeps native CLI schema enforcement instead of falling back to post-validation over stream-json
• add coverage in tests/template-resolver.test.js to assert the resolved tester agent preserves strictSchema: true

Testing

• ./node_modules/.bin/mocha tests/template-resolver.test.js tests/type-safety-validation.test.js

Checklist

• Tests pass (npm test)
• Documentation updated (if needed)
• Follows commit guidelines