Soft/hard crash on ep3 credits

Some users have reported a soft crash when the ep3 credits load. It looks like either the credits image doesn't load at all, or my scrolling code doesn't scroll the credits image properly.

See: https://www.twitch.tv/videos/432874492 (very end of the video) and https://www.twitch.tv/videos/432919029 (10m7s)

In the mean time, I have put an extra check before the credits which have variable lengths to limit the maximum credits time, incase the timer is getting corrupted or my maths is bad causing an extremely long credits scroll time.

I tested the ending on my netbook with integrated intel graphics / bad cpu and it still ran OK.

該 issue 涉及第 3 集的演職員表序列。檢查演職員表的載入和捲動程式碼，可能位於場景或 UI 管理器中。檢查圖像載入邏輯和捲動計時器的計算。使用提供的 Twitch 影片時間戳重現問題，以了解崩潰的上下文。驗證限制最大演職員表時間的臨時修復。

由索引模型根據 Issue 內容生成。