[Bug] Anthropic API Error: Model access denied for claude-opus-5

**Bug Description**
we are as swiss grc CVP flagged, but can't use opus 5 to test our applications

**Environment Info**
- Platform: win32
- Terminal: windows-terminal
- Version: 2.1.274
- Feedback ID: a98087ea-79cd-480a-9098-8bd735892646

**Errors**
```json
"Opus 5's safeguards flagged this message. Our intentionally broad safeguards allow us to deliver more capabilities faster, but can sometimes flag legitimate coding, cybersecurity, and biology tasks. Switched to Opus 4.8"
```

Start by reproducing the report in the stated win32 and Windows Terminal environment with version 2.1.274, using the provided error text and feedback ID to trace the model-access failure. Determine whether the denial is reproducible and what expected behavior is for legitimate requests; the issue currently names no source file, test, or concrete change.

Written by the indexing model from the issue text.