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/useIsMounted.ts

@@ -0,0 +1,19 @@
+import * as React from "react";
+
+/**
+ * Hook to check if component is still mounted
+ *
+ * @returns {boolean} true if the component is mounted, false otherwise
+ */
+export default function useIsMounted() {
+  const isMounted = React.useRef(false);
+
+  React.useEffect(() => {
+    isMounted.current = true;
+    return () => {
+      isMounted.current = false;
+    };
+  }, []);
+
+  return React.useCallback(() => isMounted.current, []);
+}