# P5 Artifact-Only Road Package Design

P5 replaces the current runtime dependency boundary with a file-only boundary:

```text
road-compiler Web editor
  -> deterministic root-flat native-road-package/v1.1 ZIP
  -> osmWorkflow config nativeRoadPackage
  -> private verified extraction cache
  -> Blender / Cesium / preview
```

The road-compiler repository owns export and all editing/compiler internals. osmWorkflow owns ZIP safety,
contract validation, Blender materials and downstream scene construction. Neither repository reads the
other's source, configuration, overrides or runtime implementation.

The ZIP is immutable input and the host's `_pipeline/native-road-import/<sha256>` is disposable cache.
The host rejects unsafe archive topology before writing files, then validates v1.1 `manifest.json` and
area identity before starting Blender. Stage manifests record the ZIP hash and resolved package records.

P5A publishes a fixture/exporter first. P5B uses that fixture to remove compiler CLI installation and
invocation from the host. The migration is intentionally a contract-preserving transport change: rendered
geometry and material behavior must remain at the P3 baseline.