Propagate multi-message system prompts and token usage

[karashiiro]

• The system prompt is actually two messages in Claude Code, so we need to handle the array case of it to actually get the real Claude Code system prompt here
• Token usages need to be mapped back from OpenRouter to Claude or else there's an input_tokens error sometimes after pasting content into the chat
• Added debug logging for the raw request for future use

Validated via debug logging and live usage.

[karashiiro]

??

[MikkoParkkola]

Hey sorry, I was playing with your fork with claude code as I run into the same issues, and it seemed to do a bit of free style comments of its own automatically. Comments removed.