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/menus/separator.ts

@@ -0,0 +1,7 @@
+import { MenuSeparator } from "~/types";
+
+export default function separator(): MenuSeparator {
+  return {
+    type: "separator",
+  };
+}