frames-v2

two small things it could be helpful to have that i've noticed after working with /frames-v2 a little bit, either from the farcaster frame sdk directly or from the community:
- another open source tool to generate the domain account association json (another open source frames v2 previewer would be nice too but i feel like the json would be more helpful at first, espc on web)
- info in the context telling me if the user's warpcast is in light or dark mode(eg. my personal sites uses the browser's light & dark mode toggles, if i had warpcast's i could sync that too to make it blend in more)