feat: add Kilo Code (kilocode) as first-class inference provider (#1666)

Add Kilo Gateway (kilo.ai) as an API-key provider with OpenAI-compatible
endpoint at https://api.kilo.ai/api/gateway. Supports 500+ models from
Anthropic, OpenAI, Google, xAI, Mistral, MiniMax via a single API key.

- Register kilocode in PROVIDER_REGISTRY with aliases (kilo, kilo-code,
  kilo-gateway) and KILOCODE_API_KEY / KILOCODE_BASE_URL env vars
- Add to model catalog, CLI provider menu, setup wizard, doctor checks
- Add google/gemini-3-flash-preview as default aux model
- 12 new tests covering registration, aliases, credential resolution,
  runtime config
- Documentation updates (env vars, config, fallback providers)
- Fix setup test index shift from provider insertion

Inspired by PR #1473 by @amanning3390.

Co-authored-by: amanning3390 <amanning3390@users.noreply.github.com>

hermes_cli/doctor.py

@@ -46,6 +46,7 @@ _PROVIDER_ENV_HINTS = (
     "KIMI_API_KEY",
     "MINIMAX_API_KEY",
     "MINIMAX_CN_API_KEY",
+    "KILOCODE_API_KEY",
 )
 
 
@@ -571,6 +572,7 @@ def run_doctor(args):
         ("MiniMax",          ("MINIMAX_API_KEY",),                            None,                                  "MINIMAX_BASE_URL", False),
         ("MiniMax (China)",  ("MINIMAX_CN_API_KEY",),                         None,                                  "MINIMAX_CN_BASE_URL", False),
         ("AI Gateway",       ("AI_GATEWAY_API_KEY",),                          "https://ai-gateway.vercel.sh/v1/models", "AI_GATEWAY_BASE_URL", True),
+        ("Kilo Code",        ("KILOCODE_API_KEY",),                            "https://api.kilo.ai/api/gateway/models",  "KILOCODE_BASE_URL", True),
     ]
     for _pname, _env_vars, _default_url, _base_env, _supports_health_check in _apikey_providers:
         _key = ""