Convert to Docker

This skill migrates NanoClaw from Apple Container (macOS-only) to Docker for cross-platform support (macOS and Linux).

What this changes:

• Container runtime: Apple Container → Docker
• Mount syntax: --mount type=bind,...,readonly → -v path:path:ro
• Startup check: container system status → docker info
• Build commands: container build/run → docker build/run

What stays the same:

• Dockerfile (already Docker-compatible)
• Agent runner code
• Mount security/allowlist validation
• All other functionality

Prerequisites

Verify Docker is installed before starting: