Google OAuth Invalid Grant

Hey, great tutorial. I wanted to get some more control over how the access token jwt get managed and this pretty much covers all the stuff I'm too lazy to go digging for myself.

When implementing, I ran into an issue with invalid grant errors. I haven't reproduced this in your project so I don't know if you've run into this so if you or anyone else does, here's what I did:

1. authWithOauth2 is deprecated - switch to authWithOauth2Code (same signature)
2. per the answer here. codeVerfier gets changed every time you call listAuthMethods().
   1. I fixed this by returning the authProvider.codeVerifier in /login/+page.server.ts (just like the state) and then putting the authProvider.codeVerifer on a cookie (again just like state) and finally catching that off the cookie in /callback/server.ts .