0002 — Dual-target dbt: DuckDB dev, BigQuery prod¶

Status: accepted

BigQuery is the production warehouse from day one; DuckDB is the dev target for free, fast local iteration. There is no migration — prod is BigQuery from the first commit. Cost: SQL must stay dialect-compatible; dialect-specific logic lives in dispatch macros. V2's BigQuery AI functions are prod-only (stubbed on the dev target). This also keeps CI secret-less (it runs on DuckDB), which is safe for a public repo's fork PRs.