Task 8 commit f9a1548 added `schema_version: String` as required field on
ErrorV1 (so kebab-mcp's direct serialize-then-emit path produces correct
error.v1 wire). The wire.rs ErrorV1 literal in the
error_wrapper_tags_schema_version_and_emits_code test was missed —
breaks kebab-cli build. Add the field to the test fixture.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>