powercontext.yaml is copied from the current Python reference baseline and is
the sole source of truth for HTTP wire generation.
OpenAPI 3.0 cannot encode the combined source_refs + artifact_refs maximum
described by the Candidate schemas. The generator derives the affected model
set from the two maxItems: 32 declarations and emits the supplemental
api/v1.ValidatePowerContextContract validator. HTTP, MCP, and the public Go
Client all invoke it at their decoded transport boundary.