connect_timeout is applied per resolved address, not per endpoint

`connect_stream` applies `connect_timeout` **per resolved address**, not per endpoint, contradicting the doc comment ("TCP connect timeout per endpoint attempt"). A hostname resolving to two addresses multiplies every bound: measured 2.0011s for two blackhole addresses at a 1s timeout.

Fix: give `connect_stream` a single total deadline across all resolved addresses, so the timeout bounds the endpoint attempt as documented.

先閱讀 connect_stream 及其 connect_timeout 文件註解，接著重現 issue 中描述的雙位址情況，以確認目前按位址計算的計時。完成的標準是所有已解析的位址共用一個總截止時間，讓端點嘗試維持在文件所述的逾時範圍內。

由索引模型根據 Issue 內容生成。