Phase 106 — verify exported host artifact

At a glance

Field	Value
Phase family	Phase 1 — first stones
Run command	`make phase 106`
Underlying make target/script	`vm/phase1/verify-exported-repo.sh`
Runs on	host
Main proof/artifact	Verifies the exported repo artifact, checksums, metadata, and gitignore protection.

Phase 106 is host-only. It does not SSH into the forge VM.

It verifies:

artifacts/onix-publish/repo.json exists and names ONIX correctly
homepage is https://onix-os.com
source is https://github.com/onix-os
future repo hint is https://repo.onix-os.com/unstable/x86_64/stone.index
exactly one onix-branding stone exists
exactly one onix-filesystem stone exists
SHA256SUMS validates
no Moss test state (.moss, moss-root, moss-cache, install-target) leaked into the artifact
artifacts/ is gitignored

This gives us a clean gate before any future upload/publish phase.