feat: add OrcaRouter as a named LLM provider

[XiaoHuo888-hue]

Problem

Lingo.dev supports several named LLM providers out of the box (OpenAI, Anthropic, Google, Groq, Mistral, OpenRouter, Ollama). There is no first-class provider entry for a smart-routing OpenAI-compatible gateway, so users who want to route all translations through such a gateway have to rely on the generic OPENAI_BASE_URL override (see #1729) and a hand-written provider:model string.

Solution

Add OrcaRouter as a named provider. OrcaRouter is an OpenAI-compatible LLM gateway with a smart routing model (orcarouter/auto). Adding it as a first-class provider entry mirrors the existing OpenRouter wiring and gives users a discoverable, documented option instead of a generic passthrough.

It also runs gateway-level, zero-trust security for AI agents on the same endpoint — screening every prompt/response and governing every tool call on a default-deny basis, with no application code changes.

Implementation sketch (mirrors the existing OpenRouter provider):

• New orcarouter case in createAiModel (new compiler) that builds an OpenAI-compatible client pointed at https://api.orcarouter.ai/v1 with ORCAROUTER_API_KEY.
• New orcarouter entry in providerDetails (new compiler + legacy compiler), the CLI settings schema, llm-api-key.ts, and the CLI processor / explicit localizer.
• Update the providerSchema enum in @lingo.dev/_spec.
• Add ORCAROUTER_API_KEY to docs and .env examples.

Alternatives

• Leave users to the generic OPENAI_BASE_URL passthrough (Add openAI compatible provider #1729). This works but offers no discoverable, named integration and no provider metadata (key links, config keys).

Checklist

• Add named orcarouter provider across the provider registries
• Add tests
• Add changeset

[XiaoHuo888-hue]

Hi maintainers — this feature request adds OrcaRouter as a first-class named LLM provider, mirroring the existing OpenRouter wiring. I'd like to implement it (new-compiler createAiModel case + providerDetails entries, CLI settings, @lingo.dev/_spec provider enum, docs/tests/changeset). Could you please assign me? Thanks!

[XiaoHuo888-hue]

PR is up: #2201 — implements OrcaRouter as a named provider across the CLI, both compilers, and the spec, with tests, docs, and a changeset. Verified locally (build + unit tests + a live end-to-end call through the OrcaRouter gateway). Thanks!