- alibaba-coding-plan-cn / alibaba-token-plan-cn keep the shared intl key vars
as ordered fallbacks after their dedicated *_CN_API_KEY, so users who set
ALIBABA_CODING_PLAN_API_KEY / ALIBABA_TOKEN_PLAN_API_KEY for the CN endpoint
keep working (the PR as filed dropped them).
- list_authenticated_providers hides a '-cn' row whose only lit key vars are
ones it shares with its non-CN sibling, unless that CN provider is the
configured model.provider. With only the shared key: one row, not two;
DASHSCOPE_API_KEY alone: 3 alibaba rows, not 4.
- Docs: environment-variables.md, providers.md.