refactor(merge,split,json): adopt streaming approach and standardize types, address gradle warnings (#5803)

Co-authored-by: Anthony Stirling <[email protected]>
Co-authored-by: Balázs <[email protected]>

frontend/src/global.d.ts

@@ -26,4 +26,16 @@ declare module 'axios' {
   }
 }
 
-export {};
+declare module 'posthog-js/react' {
+  import { ReactNode } from 'react';
+  import posthogJs, { PostHogConfig } from 'posthog-js';
+
+  export const PostHogProvider: React.FC<{
+    client?: typeof posthogJs;
+    options?: Partial<PostHogConfig>;
+    apiKey?: string;
+    children?: ReactNode;
+  }>;
+}
+
+export { };