Add k3d and Tilt support

[suin]

Summary

Adds k3d as a Kubernetes-ready distribution alongside kind and adds Tilt sample support for local registry auto-detection.

Changes

• Add k8s: kind|k3d / --k8s=kind|k3d configuration and CLI flow.
• Detect k3d API server endpoints through the k3d load balancer container.
• Detect k3d local registries and print REGISTRY for the restored VM Docker daemon.
• Update local-registry-hosting so tools such as Tilt can use local registry auto-detection.
• Add k3d registry E2E coverage.
• Add examples/k3d and examples/tilt samples.
• Update README with kind, k3d, and Tilt user guides.
• Remove the Intel macOS CI job because it cannot build the required VZ save/restore APIs.
• Add a PR template section for declaring manual macOS VZ test results.

Impact

Users can now choose k3d for spind Kubernetes-ready environments and use a k3d local registry from the DOCKER_HOST printed by spind. Tilt users can rely on k3d local registry auto-detection without adding default_registry() to the Tiltfile.

macOS VZ coverage is now handled as an explicit PR declaration instead of a GitHub-hosted Intel macOS CI job.

Validation

• task check
• task e2e
• bunx oxfmt --check .
• Manual ../../bin/spind up from examples/k3d after fixing the k3d sample readiness wait
• macOS VZ CI is not run on GitHub-hosted runners; PRs now declare whether task ci:macos was run manually on physical Apple Silicon macOS.