feat(ai): support for openrouter models

[PhantomInTheWire]

Summary of Changes

• Add OpenRouter support.
• Grok-4, llama4, claude 4 sonnet support through openrouter.
• alternative way to use gemini2.5 and gpt4.1 through open router

Related Issue

• Closes: #93, #133

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Additional Context

There is currently no real-time STT in OpenRouter that I could find.
We can potentially add support for every model on openrouter but that would need a bit of refactoring and some changes on the ui side

[PhantomInTheWire]

@ekim425 @samtiz @jhyang0 @entry-sanio can one you please review this?

[PhantomInTheWire]

@ekim425 @samtiz @jhyang0 @entry-sanio guys do we plan on merging this?