### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

When adding a Generic Guardrail API guardrail via the Admin UI (Guardrails → Add New Guardrail → Add Provider Guardrail), selecting "Generic Guardrail API" as the provider renders the UI as "No configuration fields available for this provider." The expected API Base, API Key, and other configuration fields never appear, making it impossible to configure this guardrail type through the UI.

**What did you expect to happen?**

The UI should show configuration fields for: - **API Base** (required — the guardrail endpoint URL) - **API Key** (optional) - Plus the optional parameters (unreachable_fallback, fail_on_error, streaming_end_of_stream_only, streaming_sampling_rate, streaming_transform_mode)

### Steps to Reproduce

1. Navigate to Admin UI → Guardrails → Add New Guardrail → Add Provider Guardrail 2. In **Guardrail Name**: enter any name (e.g. "llm-guard") 3. In **Guardrail Provider**: select **Generic Guardrail API** 4. In **Mode**: select `pre_call` and `post_call` 5. **Always On**: toggle on 6. Observe the Provider Configuration section sh…