schema.v1: full introspection report shape with required fields for
wire / capabilities / models / stats. capabilities object enumerates
all 10 flag names (current 6 true + future 4 false) as required keys.
error.v1: 7-code enum + permissive details object. Real emitted
details shapes documented in description (per-code context varies and
some fields are interim until IoFailure / OpTimeout typed signals
land in follow-up).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>