API and configuration stability

The stable top-level names are:

Name	Contract
load_config(path)	Load and validate schema-version-1 TOML, resolving referenced files relative to the TOML.
WavefrontSensor(config)	Construct one cached optical/detector pipeline; call photon_rate, expose, expose_many, or expose_integrated with phase/OPD arrays. expose and expose_integrated optionally accept caller-owned out storage with an explicit alias lifetime.
simulate(config, wavefront, ...)	One-shot convenience wrapper around the same pipeline.
WFSConfig / Config	Frozen normalized configuration value; Config is a compatibility alias of WFSConfig.
ConfigError	Validation exception for actionable configuration failures.
__version__	Package version metadata.

The three workflow names are the recommended minimal API. Configuration types and ConfigError are public to support typed callers and validation UIs, but runtime engines, detector adapters, source-state classes, and numerical helper functions are intentionally not re-exported from makewfs.

The complete schema key inventory is maintained in configuration.md; the strict loader rejects unknown keys. Every new physical field must be documented there, validated, covered by a regression test, and recorded in the changelog before it is considered stable.

The physical per-frame contract is a wavefront array plus configuration (and an optional detector seed). out controls storage lifetime only and cannot change the simulated result. Atmosphere, reconstruction, controllers, and detector physics remain outside the package boundary.