chore: Move to Typescript (#2783)

This PR moves the entire project to Typescript. Due to the ~1000 ignores this will lead to a messy codebase for a while, but the churn is worth it – all of those ignore comments are places that were never type-safe previously.

closes #1282

app/hooks/useCurrentUser.ts

@@ -0,0 +1,8 @@
+import invariant from "invariant";
+import useStores from "./useStores";
+
+export default function useCurrentUser() {
+  const { auth } = useStores();
+  invariant(auth.user, "user required");
+  return auth.user;
+}