Artifact output routing

VibePro uses .vibepro/config.json as the tracked repository contract for canonical artifact locations. vibepro init ignores generated workspace files while leaving this config trackable.

Without artifact_routing, all paths remain backward-compatible. To place a feature packet under one project-native directory:

{
  "artifact_routing": {
    "schema_version": "0.1.0",
    "artifacts": {
      "story": { "canonical": "docs/features/{feature_slug}/01_behavior_spec.md" },
      "architecture": { "canonical": "docs/features/{feature_slug}/04_technical_delta.md" },
      "accepted_spec": { "canonical": "docs/features/{feature_slug}/02_functional_spec.json" },
      "task_plan": { "canonical": "docs/features/{feature_slug}/06_tasks.md" }
    }
  }
}

Supported stable variables are {story_id} and {feature_slug}. Both are lowercase kebab-case; feature_slug removes a leading story-. Paths must be repository-relative. Absolute paths, traversal, unresolved variables, and destinations shared by two artifact kinds fail before a write.

Each kind has exactly one writable canonical. A projection is allowed only when explicitly machine-managed:

{
  "path": "docs/generated/{story_id}/architecture.md",
  "generated": true
}

Projections are rebuildable views, not editable sources of truth.

Inspect the contract and plan a migration without editing files:

vibepro artifacts resolve . --id story-example --json
vibepro artifacts migrate . --id story-example --dry-run --json

The migration plan reports the old default, resolved destination, existence, required moves, and collisions. Move tracked artifacts only after reviewing that plan.

Rollback is not a config-only operation. The migration plan compares the default source with the destination resolved from the current config. If you remove artifact_routing first, VibePro cannot infer the custom destination that was in use. Before removing the setting, save the dry-run source/destination mapping and review collisions and ownership. Move the custom artifacts back to the legacy defaults from that saved mapping, verify the result without overwriting existing files, and only then remove artifact_routing. If the setting was already removed, recover the mapping from the pre-change config or Git history; a fresh dry-run after removal cannot reconstruct the old custom layout.