pi-container-sandbox v1.1.0

Changes

• Podman runtime support: New PodmanRuntime with rootless compatibility and cgroups degradation
• Engine configuration: engine field in sandbox.json (docker/podman/auto)
• Auto-detection: auto mode prefers podman, falls back to docker
• Resource limits: Only passed to CLI when explicitly configured (no more tier defaults)
• Removed tier: tiers.ts, /sandbox tiers command, tier config field removed
• Architecture: container-cli.ts parameterized binary layer, DockerRuntime refactored, PodmanRuntime added