fix: CLI ErrorCode reuse + result_type→renderer parity contract test #307

Job	Run time
pytest (ubuntu-latest)	1m 21s
Frontend unit tests (vitest) (macos-latest)	28s
API integration tests + coverage (windows-latest)	1m 5s
API integration tests + coverage (ubuntu-latest)	20s
ruff + pip-audit (ubuntu-latest)	24s
Frontend unit tests (vitest) (windows-latest)	1m 5s
ruff + pip-audit (windows-latest)	1m 41s
Frontend unit tests (vitest) (ubuntu-latest)	27s
Verify prod requirements.txt is sufficient	7s
pytest (windows-latest)	1m 28s
pytest (macos-latest)	32s
Performance benchmarks (gated)	28s
mypy	20s
ruff + pip-audit (macos-latest)	22s
API integration tests + coverage (macos-latest)	24s
	10m 32s

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