Introduces bin/yino-vm with create, boot, delete, and status subcommands for managing a QEMU x86_64 VM on macOS. Auto-detects OVMF firmware paths and CPU/accelerator (HVF on Intel, TCG on Apple Silicon). VM artifacts are stored in vm/ (gitignored). Completes TODO #1. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>