This directory owns durable cross-cutting architecture rules that are broader than one subsystem but still normative enough to guide implementation and tests.

Index

MODULE_LAYERS.md: source-module dependency layers, promotion rules, and reusable subsystem boundaries.
SCENE_SPLIT_REFACTOR_PLAN.md: concrete plan for promoting scene-independent primitives out of the retained scene layer.
EXTERNAL_DEPENDENCIES.md: policy for optional third-party dependencies such as UI integration layers.

Boundary

Put a document here when it constrains multiple source modules, build targets, public headers, or release artifacts. Keep subsystem-specific contracts in their owning directory, such as drp2/, scene/, api/, bindings/, build/, or testing/.