fix: update OpenRouter Trinity model names to include (free) suffix

[ruben-blok]

Fixes #12200

Update model names for OpenRouter free tier models:

• Trinity Mini -> Trinity Mini (free)
• Trinity Large Preview -> Trinity Large Preview (free)

This makes it clearer which models are free tier on OpenRouter.

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential duplicate found:

• PR feat: Trinity model support #12144: feat: Trinity model support

  Why it's related: This PR adds Trinity model support to OpenRouter, while PR fix: update OpenRouter Trinity model names to include (free) suffix #12199 updates those same Trinity model names to include the "(free)" suffix. These PRs likely overlap in scope - PR feat: Trinity model support #12144 may have added the Trinity models without the free tier naming convention, and PR fix: update OpenRouter Trinity model names to include (free) suffix #12199 is updating those names. Check if PR feat: Trinity model support #12144 is already merged or if these should be consolidated.