Add Huawei Cloud MaaS provider

[araujoviana]

Summary

Add Huawei Cloud ModelArts MaaS (Model-as-a-Service) as a new provider with 8 models.

Provider

• OpenAI-compatible API at https://api-ap-southeast-1.modelarts-maas.com/openai/v1
• Uses @ai-sdk/openai-compatible npm package
• Env var: HUAWEI_CLOUD_MAAS_API_KEY

Models

Model	Approach	Notes
glm-5.1	extends zai/glm-5.1	Huawei pricing with cost tiers at 32K context
glm-5	extends zai/glm-5	Huawei pricing with cost tiers at 32K context
deepseek-v4-pro	extends deepseek/deepseek-v4-pro	Huawei pricing
deepseek-v4-flash	extends deepseek/deepseek-v4-flash	Huawei pricing
deepseek-v3.2	full definition	Reasoning model (deepseek-thinking family)
deepseek-v3.1-terminus	full definition	Reasoning model (deepseek-thinking family)
deepseek-r1-250528	full definition	Fixed temperature (0.6), reasoning model
DeepSeek-V3	full definition	Capital D/S per Huawei model ID

Validation

• bun validate passes
• bun run build (packages/web) passes