OrcaRouter provider support for ClojureMCP

ClojureMCP solves a problem Clojure developers know well: generic coding assistants are unreliable at the language's structure. The project's answer is a REPL connection that repairs delimiters before evaluation, plus structure-aware editing built on parinfer, cljfmt, and clj-rewrite that targets forms by type and name instead of text matching. That is what makes an LLM trustworthy enough to edit and validate code in a live nREPL.

ClojureMCP also exposes a configurable model layer. Its agent tools — `dispatch_agent`, `architect`, `code_critique` — read the `:models` map in `.clojure-mcp/config.edn`, where a provider is an OpenAI-compatible `:base-url` plus an API key (Mistral ships exactly that way as `:provider :openai`). An extra OpenAI-compatible provider therefore means more real model choice for agent-tool users, with no new provider client to maintain.

## Proposal: add OrcaRouter as an optional provider

I'm an engineer on the OrcaRouter team, and I'd like to propose supporting [OrcaRouter](https://www.orcarouter.ai) as an optional model provider for ClojureMCP. This would not replace or alter any existing provider — the Anthropic, OpenAI, Google, and Mistral entries and their env-var keys would stay as they are. It would simply let users who want it point their model configuration at OrcaRouter.

For ClojureMCP's users, the most relevant OrcaRouter capabilities are:

- **Multiple chat and reasoning models behind one endpoint**, so agent tools can reach different models without maintaining several per-provider configs.
- **Automatic model routing with provider failover**, which matters during long `dispatch_agent` runs where a single provider outage would otherwise abort the work.
- **Usage tracking and budgets**, which keep the API charges the README warns about predictable when agent tools are used regularly.

OrcaRouter exposes an OpenAI-compatible API and uses standard API-key authentication. The expected integration point is the model-configuration path in `doc/model-configuration.md`: users would add a `:models` entry with an OrcaRouter `:base-url` and an API key via the documented `[:env "VAR"]` pattern. Nothing is implemented or tested here — this is a proposal to gauge interest before any code.

OrcaRouter is already part of the open-source LLM ecosystem, with integrations alongside projects such as goose, promptfoo, and models.dev / OpenCode.

One transparent note: OrcaRouter runs an optional open-source partner program in which approved OSS projects can receive a 5% revenue share from OrcaRouter usage attributed to their integration. Participation is not a prerequisite for integrating, and I'm happy to follow whatever disclosure or governance rules the project prefers.

You can see other open-source projects we work with at https://www.orcarouter.ai/built-with. Would ClojureMCP supporting OrcaRouter as an optional provider be of interest? If so, I'd be glad to submit an implementation PR once you approve the direction.

Start with doc/model-configuration.md and the existing :models configuration described there, especially the OpenAI-compatible :base-url and [:env "VAR"] patterns. Confirm how an optional OrcaRouter entry can be documented or wired without changing existing providers; done means users can configure it while current provider entries remain unchanged.

Written by the indexing model from the issue text.