docs: drop the click-to-enlarge caption from README screenshots

GitHub markdown can't host an in-page lightbox or prev/next carousel —
all <script> is stripped server-side, so a clickable thumbnail can only
ever open the raw image in a new page. The hint line was misleading
about that interaction, so just remove it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -20,8 +20,6 @@ Free to play, no setup required: [infiplot.com](https://infiplot.com)
 
 ## 📸 Screenshots
 
-<sub><em>click any screenshot to view full size</em></sub>
-
 <table>
   <tr>
     <td><a href="docs/screenshots/4.webp"><img src="docs/screenshots/4.webp" width="280" alt="School rooftop scene"></a></td>

README.zh-CN.md

@@ -20,8 +20,6 @@ InfiPlot是一款AI实时生成内容的互动剧情游戏，这里没有预设
 
 ## 📸 游戏截图
 
-<sub><em>点击任意截图可查看大图</em></sub>
-
 <table>
   <tr>
     <td><a href="docs/screenshots/4.webp"><img src="docs/screenshots/4.webp" width="280" alt="高中天台黄昏对话"></a></td>