feat(db): materialize static query metadata

[sanohiro]

Summary

• publish the complete D12 metadata record/option surface and the first useful meta_query consumer
• generate one producer-owned, allocation-free QueryMeta thunk per static Query and extend the execution descriptor with its exact validated ABI
• materialize exact Names/Summary/Full projections into the caller region across whole-program and per-unit builds, rejecting malformed descriptors and non-live execution targets before thunk work

Review closure

The pre-open host review found one P2: a poisoned SQLite connection retained its driver byte and could pass dispatch without a complete live-state check. The final change validates the shared resource prefix's version, selected driver, closed byte, reserved field, and native pointer after driver restriction. A focused runtime owner covers each invalid field and restoration to the valid path. The same-class audit covers both drivers through their common prefix.

The cumulative gate also exposed a pre-D12 synthetic static-input fixture. It now declares the exact QueryMeta nominal surface; production generation remains fail-closed with no optional materializer path.

Verification

• pkg_db_q5b1::meta_query_rejects_non_live_execution_targets_before_materialization
• scripts/test-pr.sh
• scripts/cargo.sh clippy --workspace --lib --bins --locked -- -D warnings
• final-SHA scripts/pre-pr.sh attestation with the reviewed candidate recorded as findings-fixed