coreapi: refresh spec — tolerate unknown response fields

Upstream flipped all 54 schemas from additionalProperties: false to true. Regenerating turns the generated decoders from strict (hard-error unexpected field %q) into tolerant (unknown fields captured into an AdditionalProps map), so a new field on any core API model no longer breaks the CLI.

Refreshed via curl ... openapi.json + go generate ./internal/coreapi/....