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. To roll back routing, remove artifact_routing; VibePro resumes the legacy defaults. Move files back according to a fresh dry-run if the custom layout was already committed.