Add harness app: agent orchestrator with cluster deployment

- Next.js app for orchestrating coding agent benchmarks (Claude Code, Codex, OpenCode)
- Dockerfile installs git, gh CLI, and agent CLIs for headless execution
- K8s deployment with workspace volume, sealed credentials for Claude + OpenCode
- Traefik IngressRoute at harness.coreworlds.io with internal-only middleware + TLS
- CI pipeline path filter for harness builds
- Fix OpenCode runtime flags (subcommand-based headless mode)

apps/harness/next-env.d.ts

@@ -0,0 +1,6 @@
+/// <reference types="next" />
+/// <reference types="next/image-types/global" />
+/// <reference path="./.next/types/routes.d.ts" />
+
+// NOTE: This file should not be edited
+// see https://nextjs.org/docs/app/api-reference/config/typescript for more information.