plugins/telemetry/v1.9.1

## Plugin Release: telemetry v1.9.1

- feat: A2A operation metrics export (#8575)
- chore: upgraded core to v1.13.0 and framework to v1.10.0

## 🐞 Fixed

- **Active Requests Gauge** - `bifrost_active_requests` no longer drifts upward when clients cancel streaming requests before the stream starts (for example HTTP 499 while waiting for upstream headers), or when a plugin rejects a streaming request. Each request now holds at most one slot and releases it exactly once, so dashboards and alerts built on the inflated value will see lower, correct numbers

### Installation

```bash
# Update your go.mod to use the new plugin version
go get github.com/maximhq/bifrost/plugins/telemetry@v1.9.1
```

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_This release was automatically created from version file: `plugins/telemetry/version`_