feat: support async table loads and append mode

[hotdata-automation]

Auto-generated from the updated HotData OpenAPI spec.
Source: https://github.com/hotdata-dev/www.hotdata.dev/pull/254

Also completes the regen by hand: results and query runs are now scoped to a database via the required X-Database-Id header, so the hand-written ergonomic layer (query.py, arrow.py) threads a database_id through the result/query-run helpers and query()'s truncation auto-follow. Without this the package's unit/integration tests fail against the regenerated signatures. Mirrors sdk-rust#84.

[claude]

Auto-generated SDK regeneration from the OpenAPI spec update. Reviewed the substantive model and API changes — new async load fields with correct ge=1000 validation, append mode, and the required x_database_id header threaded consistently through the query-runs and results APIs. Generated code is internally consistent. LGTM.

[claude]

Reviewed the generated OpenAPI regen and the hand-written ergonomic layer. The x_database_id threading through auto-follow (query → _materialize_full → wait_for_result/_authoritative_total/_fetch_all_rows) and the arrow helpers is consistent, the header-vs-body database source fallback is sound, breaking signature changes are documented in the CHANGELOG, and both paths are covered by tests. LGTM.