Use steam ID for reliable, persistent CL user auth

auth/src/cardlife/temporary_get_user_id.rs

@@ -3,10 +3,11 @@ use rocket::{post, routes, serde::json::Json};
 
 #[post("/api/auth/temporarygetuserid", data = "<body>")]
 pub fn temp_migration(body: Json<libfj::cardlife::TempGetUserIdPayload>) -> Json<libfj::cardlife::TempGetUserIdResponse> {
+    let steam_id = uuid::Uuid::parse_str(&body.public_id).map(|guid| guid.as_u64_pair().0).unwrap_or(123456);
     Json(libfj::cardlife::TempGetUserIdResponse {
         public_id: body.public_id.to_owned(),
         token: body.token.to_owned(),
-        user_id: 123456, // FIXME
+        user_id: (steam_id & (i32::MAX as u64)) as i32,
     })
 }