fix: force tool parameter passthrough for OpenRouter models

[roomote-v0]

Related GitHub Issue

Closes: #11968

Description

This PR attempts to address Issue #11968 where Nemotron 3 Super 120b-a12b (and potentially other models) produce broken output when used through OpenRouter.

Root cause: When OpenRouter's metadata does not list tools in a model's supported_parameters, OpenRouter may either strip the tool parameters or apply prompt-based transforms that produce poor results (e.g. wrapping output in [{code here}] formatting). This happens even for models like Nemotron 3 Super that actually support native tool calling.

Fix: Added require_parameters: ["tools", "tool_choice"] to the OpenRouter provider configuration in createMessage. This tells OpenRouter to always pass tool-calling parameters through to the underlying model, regardless of what the model's metadata says about supported parameters. This is done via the OpenRouter provider routing API.

Key changes:

• Added provider field to OpenRouterChatCompletionParams type
• Always include provider.require_parameters: ["tools", "tool_choice"] in createMessage requests
• When a specific provider is configured, the routing config (order, only, allow_fallbacks) is merged with require_parameters

Feedback and guidance are welcome.

Test Procedure

• Added 2 new unit tests verifying require_parameters is always present in the provider config
• Added test verifying require_parameters merges correctly with specific provider routing
• All 26 existing OpenRouter handler tests continue to pass
• Run: cd src && npx vitest run api/providers/__tests__/openrouter.spec.ts

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Testing: New and/or updated tests have been added to cover my changes.
• Documentation Impact: No documentation updates required.
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Interactively review PR in Roo Code Cloud