Qt AI Assistant 0.9.6 release (#31)

## Qt AI Assistant v0.9.6
# Key Changes
- GPT-5 support
- GPT-OSS 20B support

# Install
Via Qt Creator Extensions in 17.0.1+.

## Checklist

- [x] I have run `npm run all` to validate my changes
- [x] I have made sure my commits are
[signed](https://docs.github.com/en/authentication/managing-commit-signature-verification/signing-commits)
- [ ] I have added an entry for new Extensions in
[CODEOWNERS](/CODEOWNERS)

Author: cristianadam