fix(kimi): reconcile sk-kimi- routing with Anthropic SDK URL semantics

Follow-ups after salvaging xiaoqiang243's kimi-for-coding patches:

- KIMI_CODE_BASE_URL: drop trailing /v1 (was /coding/v1).
  The /coding endpoint speaks Anthropic Messages, and the Anthropic SDK
  appends /v1/messages internally. /coding/v1 + SDK suffix produced
  /coding/v1/v1/messages (a 404). /coding + SDK suffix now yields
  /coding/v1/messages correctly.
- kimi-coding ProviderConfig: keep legacy default api.moonshot.ai/v1 so
  non-sk-kimi- moonshot keys still authenticate. sk-kimi- keys are
  already redirected to api.kimi.com/coding via _resolve_kimi_base_url.
- doctor.py: update Kimi UA to claude-code/0.1.0 (was KimiCLI/1.30.0)
  and rewrite /coding base URLs to /coding/v1 for the /models health
  check (Anthropic surface has no /models).
- test_kimi_env_vars: accept KIMI_CODING_API_KEY as a secondary env var.

E2E verified:
  sk-kimi-<key>  → https://api.kimi.com/coding/v1/messages (Anthropic)
  sk-<legacy>    → https://api.moonshot.ai/v1/chat/completions (OpenAI)
  UA: claude-code/0.1.0, x-api-key: <sk-kimi-*>

tests/hermes_cli/test_api_key_providers.py

@@ -71,7 +71,11 @@ class TestProviderRegistry:
 
     def test_kimi_env_vars(self):
         pconfig = PROVIDER_REGISTRY["kimi-coding"]
-        assert pconfig.api_key_env_vars == ("KIMI_API_KEY",)
+        # KIMI_API_KEY is the primary env var; KIMI_CODING_API_KEY is a
+        # secondary fallback for Kimi Code sk-kimi- keys so users don't
+        # have to overload the same variable.
+        assert "KIMI_API_KEY" in pconfig.api_key_env_vars
+        assert "KIMI_CODING_API_KEY" in pconfig.api_key_env_vars
         assert pconfig.base_url_env_var == "KIMI_BASE_URL"
 
     def test_minimax_env_vars(self):