feat(openrouter): update model YAMLs [bot]

[harshiv-26]

Auto-generated by poc-agent for provider openrouter.

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Note

Low Risk
Low risk configuration-only updates to model metadata (features, pricing tiers, sources, provisioning/status) with no code or security logic changes.

Overview
Refreshes OpenRouter provider model YAMLs to better reflect current capabilities and metadata.

Adds provisioning: serverless (and status: active where missing) plus additional sources links for minimax-m2.5:free, grok-4.20, grok-4.20-multi-agent, and glm-5-turbo.

Extends model-specific metadata: minimax-m2.5:free now advertises system_messages, and grok-4.20-multi-agent adds tiered cache_read pricing details.

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