feat: add Astraflow provider support

[ucloudnb666]

Summary

Adds Astraflow (by UCloud / 优刻得) as a supported AI provider with both the global and China region endpoints.

Astraflow is an OpenAI-compatible model aggregation platform supporting 200+ models. Because it is OpenAI-compatible, integration reuses the existing createOpenAI SDK path — no new dependencies are required.

What was changed

File	Change
packages/shared/src/types/provider.ts	Added ASTRAFLOW and ASTRAFLOW_CN to the ProviderProtocol const/type
packages/server/src/common/ai-provider.util.ts	Added default model IDs, createLanguageModel cases, and resolveModels cases for both protocols
packages/web/src/lib/provider-constants.ts	Added default base URLs, PROTOCOL_OPTIONS entries, and PROTOCOL_CONFIG badge styles
packages/web/src/locales/en.json	Added English i18n strings
packages/web/src/locales/zh.json	Added Chinese i18n strings

Provider details

	Global	China
Protocol key	ASTRAFLOW	ASTRAFLOW_CN
Base URL	https://api-us-ca.umodelverse.ai/v1	https://api.modelverse.cn/v1
Website	https://astraflow.ucloud-global.com	https://astraflow.ucloud.cn
SDK	@ai-sdk/openai (reused)	@ai-sdk/openai (reused)

No breaking changes

All existing protocols are unaffected. The new protocols follow the exact same patterns as DEEPSEEK, ZHIPU, and MOONSHOT.