single line breaks are not preserved in the input display after submitting

### Description

for example:
```
a
b

c
```

turns into 
```
ab

c
```

but only in the display. the context/history apparently has the correct input acc. drew on discord

<img width="778" height="360" alt="Image" src="https://github.com/user-attachments/assets/70a146af-8bab-4f18-b147-bd8737b131d8" />

### Version

0.88.0

### Environment

macos / ghostty / -