Add service-level destroy endpoint

[vigneshrajsb]

Summary

• add a service-level destroy endpoint for deploy-scoped teardown
• reuse the deploy cleanup service to remove service infrastructure and mark the deploy record torn down
• change build destroy to enqueue the existing worker-owned delete flow instead of doing cleanup directly in the API request
• update the API schema and focused service tests for the new behavior

Validation

• pnpm run lint
• pnpm test
• Local end-to-end validation for service-level destroy across Helm, GitHub, and Docker service types
• Local end-to-end validation for build-level destroy through the queued worker teardown path
• pnpm run ts-check currently fails on existing repo-wide type errors outside this change