v0.2.4

Completes the #24 model-mismatch work surfaced by live testing.

Added

• First-class support for bare top-level JSON array responses via a ListResponse[Item] wrapper;
  order.get_orders and order.get_order_history now return list[...].
• Live write round-trips (save + read-back + delete, self-cleaning) for client preferences and
  watchlists.

Fixed

• client_preference.save_client_preference and watchlist.save_watchlist now succeed: their
  request bodies wrap a single object, but the models typed the field as a list, so the API
  rejected every call with HTTP 400 (#24).
• watchlist.delete_watchlist now sends its params as query parameters, which the live API
  requires (a body request 400s) (#24).

Mechanism is sound and mypy-clean (EndpointSpec/invoke/ainvoke untouched). Adversarially
reviewed with zero confirmed blockers; 1330 tests pass at 94.8% coverage.

Tracked for a follow-up in #24: user_account.get_charting_enabled (bare scalar boolean).

See CHANGELOG.md.