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>

website/docs/user-guide/configuration.md

@@ -70,6 +70,7 @@ You need at least one way to connect to an LLM. Use `hermes model` to switch pro
 | **Kimi / Moonshot** | `KIMI_API_KEY` in `~/.hermes/.env` (provider: `kimi-coding`) |
 | **MiniMax** | `MINIMAX_API_KEY` in `~/.hermes/.env` (provider: `minimax`) |
 | **MiniMax China** | `MINIMAX_CN_API_KEY` in `~/.hermes/.env` (provider: `minimax-cn`) |
+| **Kilo Code** | `KILOCODE_API_KEY` in `~/.hermes/.env` (provider: `kilocode`) |
 | **Custom Endpoint** | `hermes model` (saved in `config.yaml`) or `OPENAI_BASE_URL` + `OPENAI_API_KEY` in `~/.hermes/.env` |
 
 :::info Codex Note