feat: Integrate OpenRouter as model provider

[twilwa]

Don't think there's an issue open for openrouter, but this technically works. I'd like to clean it up a bit as I'm not certain it's priortizing correctly (character.json, .env, fallback to oai) at all steps and I haven't tested trying to change the small/med/large model at those steps, but thought I'd toss it up in case we wanted a 'fuck it, shove it in anyway' type beat lol

Relates to:

Risks

Background

What does this PR do?

What kind of change is this?

Documentation changes needed?

Testing

Where should a reviewer start?

Detailed testing steps

[lalalune]

LGTM just --

1. rebase on new, run the prettier
2. delete the unnecessary files

[twilwa]

LGTM just --

1. rebase on new, run the prettier
2. delete the unnecessary files

actually havent done a rebase berfore -- seems like it's walking through every commit on main since i opened the branch to check for conflicts, is there a way to mass-accept incoming rebase changes? otherwise 400+ 'approve me' steps

think i fixed git so its not adding my weird extra files tho

[twilwa]

mk, not exaaactly sure what i did but i think that broke everything lol. thankfully still have the cursor convo, so will try to fix and then maybe try and pair with someone to finish