Release v0.3.0

Changes

Added

• taker_fee_rate and maker_fee_rate in REST api.
• Portfolios endpoints: list_portfolios, create_portfolio, get_portfolio_breakdown, move_portfolio_funds, edit_portfolio, delete_portfolio
• Convert endpoints: create_convert_quote, get_convert_trade, commit_convert_trade
• Payment Methods endpoints: list_payment_methods, get_payment_method
• Data API endpoint: get_api_key_permissions
• Futures (CFM) endpoints: get_futures_balance_summary, list_futures_positions, get_futures_position, schedule_futures_sweep, list_futures_sweeps, cancel_pending_futures_sweep, get_intraday_margin_setting, get_current_margin_window, set_intraday_margin_setting
• Perpetuals (INTX) endpoints: allocate_portfolio, get_perps_portfolio_summary, list_perps_positions, get_perps_position, get_perps_portfolio_balances, opt_in_or_out_multi_asset_collateral
• Async mirrors of all the above in CoinbaseAwaitableRestClient, plus new data model headers (portfolio.hpp, convert.hpp, payment_method.hpp, key_permissions.hpp, futures.hpp, perpetuals.hpp) and Amount type in common.hpp

Changed

• Change log file opening mode to append for data logging
• Upgraded slick-net dependency from v2.0.0 to v2.1.0
• Changed market_data_websocket_ and user_data_websocket_ members from shared_ptr to unique_ptr
• Refactored WebSocketClient destructor to call reset_callbacks() before closing sockets, eliminating busy-wait polling loops on disconnect
• Removed atomic pending_md_socket_close_ and pending_user_socket_close_ counters
• stop() no longer resets websocket pointers; connection state is preserved for reconnect
• Disconnect callbacks no longer reset websocket pointers
• subscribe() now checks socket status to reopen a disconnected (but existing) connection instead of only creating on null
• Heartbeat subscription is now sent immediately after open() on user data socket creation

Fixed

• unsubscribe() now holds a reference to the unique_ptr instead of copying it
• double_from_json now handles fields the API returns as raw JSON numbers (not just stringified numbers), fixing parsing of PortfolioPosition.allocation/available_to_trade_fiat