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/components/DelayedMount.ts

@@ -0,0 +1,23 @@
+import * as React from "react";
+
+type Props = {
+  delay?: number;
+  children: JSX.Element;
+};
+
+export default function DelayedMount({ delay = 250, children }: Props) {
+  const [isShowing, setShowing] = React.useState(false);
+
+  React.useEffect(() => {
+    const timeout = setTimeout(() => setShowing(true), delay);
+    return () => {
+      clearTimeout(timeout);
+    };
+  }, [delay]);
+
+  if (!isShowing) {
+    return null;
+  }
+
+  return children;
+}