[Bug] Anthropic API: Claude 3.5 Opus returns corrupted output with Chinese input

**Bug Description**
I already fallback to Opus4.6

Using chinese as input with Opus5 is terrible, Opus5's response in no readable, not native chinese, a lots of weird metaphor (this also happens when using english as prompt)

and the coding experience with opus 5 is also terrible, why always over comment? write 1 line code with 10 lines of comment? is not human readable, hard to code review it's output.

**Environment Info**
- Platform: darwin
- Terminal: ghostty
- Version: 2.1.263
- Feedback ID: da858766-079f-420f-afb1-06a3e7294b21

**Errors**
```json
[]
```

No repository file, test, or entry point is named. Start by reviewing the reported Chinese and English prompts, the Anthropic API context, and feedback ID da858766-079f-420f-afb1-06a3e7294b21; done would require an agreed expected response quality and a reproducible regression check.

Rédigé par le modèle d'indexation à partir du texte de l'issue.