### Check for existing issues

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

### The Feature

## The Feature

Add support for **Huawei Cloud ModelArts MaaS (Model as a Service)** as a new LLM provider in LiteLLM.

Huawei Cloud MaaS exposes an **OpenAI-compatible** chat completions endpoint, so integration is pretty straightforward:

- **Default endpoint:** `https://api-ap-southeast-1.modelarts-maas.com/openai/v1/chat/completions` - **Auth:** Bearer token via `Authorization` header - **Docs:** [Huawei MaaS docs](https://support.huaweicloud.com/intl/en-us/usermanual-maas/usermanual_maas_0022.html)

### Models available

| Model | Context | Reasoning | Tool Calling | |-------|---------|-----------|---------------| | DeepSeek-V3 | 32K | ❌ | ✅ | | DeepSeek-V4-Pro | 1M | ✅ | ❌ | | DeepSeek-V4-Flash | 1M | ✅ | ✅ | | deepseek-v3.1-terminus | 32K | ❌ | ✅ | | deepseek-v3.2 | 32K | ❌ | ✅ | | deepseek-r1-250528 | 32K | ✅ | ❌ | | DeepSeek-V3-32K/64K/128K | 32K–128K | ❌ | ✅ | | DeepSeek-R1-32K/64K/128K | 32K–128K | ✅ | ❌ | | DeepSeek-R1-distil-Qwen-32B | 32K | ✅ | ❌ | | DeepSeek-R1-distill-LLama-70B/8B | 32K | ✅ | ❌ | | Qwen3-235B-A22B | 32K | ✅ | ✅ | |…