Design notes

These notes document current 0.3.x behavior. Planned APIs are not presented as current behavior.

• Context Ownership and Normalization
• Conversion Policy
• Dtype and Scalar-Field Behavior
• Batching and Vectorization
• Batching test policy
• Capability Dispatch
• Checking policy
• Geometry and Riesz Maps
• Performance Notes
• JAX integration
• Tree-structured spaces
• BackendOps Array API substrate
• Backend conformance
• Backend deviations
• Kernels and the optimization policy