feat(models): add OrcaRouter as a named OpenAI-compatible provider

[zsanig22-dotcom]

Summary

AgentScope Java's agentscope-extensions-model-openai already ships OpenAI-compatible providers such as Kimi, MiniMax and DeepSeek via ModelRegistry ids. This PR adds OrcaRouter the same way, mirroring compat/kimi/compat/deepseek: an orcarouter:<model> provider (e.g. orcarouter:openai/gpt-5.5, orcarouter:orcarouter/auto) that defaults to https://api.orcarouter.ai/v1, reads ORCAROUTER_API_KEY, and is registered through ServiceLoader. OrcaRouter is an OpenAI-compatible AI gateway built for both models and agents. Like OpenRouter, it exposes a provider/model namespace across many models — but it also combines adaptive routing, automatic failover, zero-markup inference, observability, guardrails, and agent-tool governance behind the same endpoint. Adding orcarouter as a first-class provider means this project's users can use that stack directly, without treating OrcaRouter as an anonymous custom base URL. 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.

Verification

• mvn -pl agentscope-extensions/agentscope-extensions-model/agentscope-extensions-model-openai -am test → BUILD SUCCESS, 566 tests, 0 failures (includes new unit + e2e tests).
• Live e2e against https://api.orcarouter.ai/v1 (orcarouter:openai/gpt-5.5) → HTTP 200.
• EN + ZH docs and provider tables updated.

I'm an engineer on the OrcaRouter team. · Discord: discord.gg/YEubt8enRA · X: https://x.com/OrcaRouter

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[oss-maintainer]

⚠️ Merge conflict detected

This PR has conflicts with the main branch and cannot be merged. Please rebase or merge main into your branch and resolve the conflicts:

git fetch origin
git checkout feat/orcarouter-provider
git rebase origin/main
# resolve conflicts, then:
git push --force-with-lease

This is a one-time reminder. Feel free to @mention me for a re-review after conflicts are resolved.

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[jujn]

Thanks for your support, we are not considering it at the moment