Architecture diagrams

Use layers-current-vs-target.mmd for reviews and onboarding. The architecture contract defines the layer rules.

Filesystem

diagrams/
├── README.md
├── layers-current-vs-target.mmd   # Canonical: current crate paths vs target seams
└── layers-legacy-names.mmd        # Historical pre-crate-rename labels (reference only)

View the sources in a Mermaid viewer or a Markdown preview with Mermaid support. layers-legacy-names.mmd keeps the old names, including workflow-core and app-backend. Do not update it for new work.