hermes - 💡(How to fix) Fix model-providers: ProviderProfile hook methods lack documented contract and test harness [1 pull requests]

Summary

The ProviderProfile class allows subclasses to override hooks such as build_extra_body, build_api_kwargs_extras, and thinking_config translation (used by Gemini, OpenRouter, etc.), but there is no documented contract, required vs optional methods list, or minimal test harness for these hooks.

Reproduction

1. Attempt to implement a custom model-provider plugin that needs per-provider request shaping.
2. Discover that the only guidance is scattered examples in existing plugins with no formal spec.

Expected behavior

A clear contract in the developer docs + a small test template that new providers can use to validate their hook implementations.

Actual behavior

Hook behavior is only visible by reading existing plugin source; no contract or test guidance exists.

Environment

• Hermes Agent (current main)
• Affects anyone building advanced model-provider plugins (especially for reasoning/thinking models or custom OpenAI-compatible endpoints)

Evidence

• website/docs/developer-guide/model-provider-plugin.md mentions overriding hooks for "per-provider quirks" but provides no contract.
• plugins/model-providers/openrouter/__init__.py and Gemini examples show real usage.
• No test file under tests/providers/ exercises the hook interface generically.
• No prior issue found for this documentation/test gap.