docs(community-providers): add Auxen

[Samp2Alex]

Summary

Adds a community-providers entry for @auxen/ai-sdk-provider, a thin wrapper over @ai-sdk/openai-compatible that targets Auxen's dedicated per-customer LLM endpoints.

What's in the package

Auxen hosts per-customer dedicated GPU instances running open-source LLMs (Llama 3.1/3.2, Qwen 2.5, Mistral, Gemma 2, Mixtral, Phi-3, Command R) on stable HTTPS endpoints with an OpenAI-compatible `/v1/chat/completions` surface. The provider exposes a `createAuxen()` factory that gives the AI SDK the right base URL + bearer auth conventions out of the box:

```ts
import { createAuxen } from "@auxen/ai-sdk-provider";
import { generateText } from "ai";

const auxen = createAuxen({
baseURL: "https://api.auxen.ai/v1/inst_xxx/v1",
apiKey: "auxk_...",
});

const { text } = await generateText({
model: auxen("llama-3.1-8b"),
prompt: "hi",
});
```

Streaming, tool calls, system messages all flow through the OpenAI-compatible wire format. ~1 KB build output.

Links

• Package: `@auxen/ai-sdk-provider` on npm
• Source: auxen-ai/ai-sdk-provider
• Auxen: auxen.ai (also has a LiteLLM provider PR in flight)

Test plan

• Built + 6/6 unit tests passing
• Live wire test against a real Auxen instance running Llama 3.1 8B (non-streaming + streaming)
• Published to npm under `@auxen` scope at v0.1.1