docs: READMEに実際のPRコメントのGIFデモを追加

README.ja.md

@@ -9,8 +9,11 @@ reg-actions の置き換え。最大の違いは **diff が緑/赤の2色**（
 
 ## 出力イメージ
 
-PR を出すと、変更があった story ごとに **expected / actual / difference** が PR コメントに並びます。
-下は QtyStepper の「+」を緑にして間隔を広げた例（difference: 🔴=旧位置 / 🟢=新位置）:
+PR を出すと、変更があった story ごとに **expected / actual / difference** が PR コメントに並びます:
+
+![chromagic PR comment demo](docs/vrt-demo.gif)
+
+下はさらに拡大した例。QtyStepper の「+」を緑にして間隔を広げたケース（difference: 🔴=旧位置 / 🟢=新位置）:
 
 ![chromagic example](docs/example-diff.png)
 

README.md

@@ -9,8 +9,11 @@ A replacement for reg-actions. The biggest difference is the **two-color green/r
 
 ## What it looks like
 
-When you open a PR, every changed story gets **expected / actual / difference** side by side in a PR comment.
-Below is a QtyStepper whose "+" was turned green and given wider spacing (difference: 🔴 = old position / 🟢 = new position):
+When you open a PR, every changed story gets **expected / actual / difference** side by side in a PR comment:
+
+![chromagic PR comment demo](docs/vrt-demo.gif)
+
+Here's a closer look — a QtyStepper whose "+" was turned green and given wider spacing (difference: 🔴 = old position / 🟢 = new position):
 
 ![chromagic example](docs/example-diff.png)