[kvlonge]

Why

Standalone SQLBuild check commands buffered Dagster check results until process completion because live checks incorrectly required an invocation-local asset materialization. SQL test fixtures also repeated typed-null projections and verbose zero-row schemas despite authoritative relation metadata.

Changes

• stream standalone audit, check, and test results to Dagster without a same-process materialization
• preserve materialization ordering for build-style commands and normalize Dagster metadata values
• infer bare NULL AS column types for expected outputs and mocked relations
• add schema-aware SELECT * FROM __empty_fixture() support
• safely remove redundant typed-null mock columns with sqb format

Verification

• Dagster resource tests: 60 passed
• focused Dagster integration regression: passed
• fixture compiler, planner, lint, integration, and DuckDB E2E tests: 102 passed
• make check-ci
• public repository hygiene scan

Tracking: CHI-320, CHI-321