[kvlonge]

Why

A target has one warehouse for every command, so ad-hoc query/diff calls wake the large build warehouse and pay its minimum resume time, while builds and plans can't use a bigger one without per-invocation edits or duplicate targets (CHI-483).

Changes

• New [targets.<name>.warehouses] build / query in sqlbuild_project.toml and sqlbuild_local.toml, plus --warehouse on every grouped command. Precedence: flag > group > connection warehouse > user default. A group overrides a connection warehouse set in a local file.
• One command-to-group table (build: audit, build, check, clone, dbt, janitor, load, plan, scenario, seed, test; query: contract, cost, debug, diff, freshness, query), enforced by a test. One warehouse per invocation for SQLBuild-owned work.
• Adapters opt in with supports_session_warehouse (Snowflake and its subclasses). Shared groups are skipped when a local adapter override lacks it; otherwise misuse is an error. Names are validated as Snowflake identifiers (C260/C261).
• sqb debug shows each group's warehouse and source.

Verification

• Unit and real-CLI integration tests (offline Snowflake double) for build, plan, query, diff, precedence, local overrides, adapters, identifiers and debug.
• One independent review plus follow-up; make test, make check-ci.