v0.23.0

Small, single-feature release on top of 0.22.0.

Changes

• chapkit test now POSTs every generated train/predict payload to /api/v1/ml/$validate before submitting the actual job (#45). Error-severity diagnostics fail the step and skip the submit; warnings and info are surfaced in --verbose only. A 404 from $validate (older service) is silently skipped, so this stays compatible with services that predate the endpoint.

Why

For runners that don't override on_validate_train / on_validate_predict, $validate only runs the framework's cheap pre-flight checks (config exists, data non-empty, prediction_periods in bounds) - exactly the smoke-test failures worth catching before burning a 60s training timeout. For runners that do override, the smoke test now exercises those hooks too. The cost is one extra HTTP roundtrip per submission, negligible against the train/predict jobs themselves.

Compatibility

• No breaking changes vs 0.22.0.
• Services older than 0.22.0's $validate endpoint are still supported - chapkit test soft-skips with a [SKIP] line in --verbose.