Summary

This fixes two hermes doctor false-negative bugs for kimi-coding-cn / Moonshot China credentials:

• treat KIMI_CN_API_KEY as a configured provider credential in .env
• make the Kimi / Moonshot (China) API probe null-safe when no base URL override env var exists

The runtime provider path is unchanged. This only corrects doctor diagnostics.

Closes #9716.

Changes

• add KIMI_CN_API_KEY to _PROVIDER_ENV_HINTS in hermes_cli/doctor.py
• guard the base URL env lookup so base_env=None does not trigger TypeError
• add regression tests for:
  • KIMI_CN_API_KEY env detection
  • Kimi China doctor probe no longer raising str expected, not NoneType

Validation

• python -m pytest tests/hermes_cli/test_doctor.py -q → 19 passed
• manual isolated repro with only KIMI_CN_API_KEY in .env now shows API key or custom endpoint configured
• Kimi China doctor probe now hits https://api.moonshot.cn/v1/models without the previous Python exception
• real runtime chat path still works with Kimi China credentials

Notes

I also checked full-suite behavior locally. The remaining local failures appear unrelated to this patch and are reproducible on a clean origin/main baseline in this macOS environment.