feat: Add Astraflow (UCloud ModelVerse) LLM provider support

[ucloudnb666]

Summary

Adds Astraflow (UCloud ModelVerse) as a supported LLM provider in DocsGPT, including both the global endpoint and the China-region endpoint.

Changes

New File

• application/llm/astraflow.py — Defines AstraflowLLM (global) and AstraflowCNLLM (China) classes, both extending OpenAILLM.

Modified Files

• application/llm/llm_creator.py — Imports and registers AstraflowLLM / AstraflowCNLLM under primary keys "astraflow" and "astraflow-cn", plus all required aliases ("astra-flow", "astra_flow", "modelverse", "astraflow-china", "astraflow_cn").
• application/core/settings.py — Adds ASTRAFLOW_API_KEY and ASTRAFLOW_CN_API_KEY fields; includes both in the sensitive-keys validator.
• application/core/model_utils.py — Adds "astraflow" and "astraflow-cn" entries to the provider-to-API-key mapping.
• application/core/model_settings.py — Adds ASTRAFLOW and ASTRAFLOW_CN to the ModelProvider enum; adds _add_astraflow_models and _add_astraflow_cn_models methods; registers them in _load_models.
• application/core/model_configs.py — Adds ASTRAFLOW_ATTACHMENTS, ASTRAFLOW_MODELS, and ASTRAFLOW_CN_MODELS lists with representative DeepSeek models.
• .env-template — Adds commented-out entries for the two new API key variables.

Naming Convention

Key	Type
astraflow	Primary key (global)
astraflow-cn	Primary key (China region)
astra-flow, astra_flow, modelverse	Aliases → astraflow
astraflow-china, astraflow_cn	Aliases → astraflow-cn

Environment Variables

ASTRAFLOW_API_KEY=<your-astraflow-api-key>
ASTRAFLOW_CN_API_KEY=<your-astraflow-china-api-key>

[vercel]

@ucloudnb666 is attempting to deploy a commit to the Arc53 Team on Vercel.

A member of the Team first needs to authorize it.