feat(api): add OrcaRouter provider

[XiaoHuo888-hue]

Add a named OrcaRouter provider for VLMEvalKit.

OrcaRouter is an OpenAI-compatible gateway that routes to frontier open-source and commercial LLMs through a single endpoint (https://api.orcarouter.ai/v1), with model strings of the form orcarouter/<model> (e.g. the special orcarouter/auto routes each request to the best available model). 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.

Changes

• New vlmeval/api/orcarouter.py: OrcaRouterAPI (a BaseAPI subclass), mirroring the existing OpenAI-compatible providers. Supports text and image (base64 image_url) inputs, ORCAROUTER_API_KEY / ORCAROUTER_API_BASE / api_base overrides, default model orcarouter/auto.
• Register OrcaRouter_Auto, OrcaRouter_DeepSeek_V4_Pro, OrcaRouter_Qwen3_5_Flash in vlmeval/config.py api_models.
• Export OrcaRouterAPI from vlmeval/api/__init__.py.
• Add tests/test_orcarouter_api.py covering init, content/message building, generate_inner, and config registration.

Verification

• pytest tests/test_orcarouter_api.py: 19 passed.
• pytest tests/test_litellm_api.py: 22 passed (regression).
• pre-commit run --all-files: all hooks pass.
• Live test: OrcaRouterAPI(model='orcarouter/auto') against https://api.orcarouter.ai/v1/chat/completions returned ret_code=0 and the expected response.

Disclosure: I'm an engineer on the OrcaRouter team.

[ssiq]

Thank you for the contribution and for adding the OrcaRouter integration.

After reviewing the implementation, we don't think a dedicated OrcaRouterAPI wrapper is necessary at this time. OrcaRouter provides an OpenAI-compatible API, and the existing LMDeployAPI already supports
OpenAI-compatible endpoints, including message construction, image/video inputs, generation parameters, retries, and streaming. OrcaRouter can be used by configuring the existing wrapper with the appropriate
api_base, API key, and model name.

The proposed wrapper largely duplicates existing functionality and would add another provider-specific code path to maintain without introducing new functionality to VLMEvalKit.

Therefore, we will close this PR for now. If there is a concrete OrcaRouter-specific behavior that cannot be handled by LMDeployAPI, please feel free to open a follow-up issue or a smaller PR focused on that
functionality. Thank you again for your contribution.