fix: add Kimi Code API support (api.kimi.com/coding/v1)

Kimi Code (platform.kimi.ai) issues API keys prefixed sk-kimi- that require:
1. A different base URL: api.kimi.com/coding/v1 (not api.moonshot.ai/v1)
2. A User-Agent header identifying a recognized coding agent

Without this fix, sk-kimi- keys fail with 401 (wrong endpoint) or 403
('only available for Coding Agents') errors.

Changes:
- Auto-detect sk-kimi- key prefix and route to api.kimi.com/coding/v1
- Send User-Agent: KimiCLI/1.0 header for Kimi Code endpoints
- Legacy Moonshot keys (api.moonshot.ai) continue to work unchanged
- KIMI_BASE_URL env var override still takes priority over auto-detection
- Updated .env.example with correct docs and all endpoint options
- Fixed doctor.py health check for Kimi Code keys

Reference: https://github.com/MoonshotAI/kimi-cli (platforms.py)

hermes_cli/doctor.py

@@ -508,10 +508,16 @@ def run_doctor(args):
             try:
                 import httpx
                 _base = os.getenv(_base_env, "")
+                # Auto-detect Kimi Code keys (sk-kimi-) → api.kimi.com
+                if not _base and _key.startswith("sk-kimi-"):
+                    _base = "https://api.kimi.com/coding/v1"
                 _url = (_base.rstrip("/") + "/models") if _base else _default_url
+                _headers = {"Authorization": f"Bearer {_key}"}
+                if "api.kimi.com" in _url.lower():
+                    _headers["User-Agent"] = "KimiCLI/1.0"
                 _resp = httpx.get(
                     _url,
-                    headers={"Authorization": f"Bearer {_key}"},
+                    headers=_headers,
                     timeout=10,
                 )
                 if _resp.status_code == 200: