feat: add new frontend components, MH batch worker, and gitignore rules

- Add all new Frontend source files (pages, components, hooks, utils)
- Add selenium_MHBatchPaymentCheckWorker.py and MHSinglePaymentCheckWorker.py
- Add install-steps-5-13.sh setup script
- Update .gitignore to exclude runtime/sensitive data (backups, uploads,
  chat-history, keys, downloads, generated .d.ts files) while keeping folders
- Add .gitkeep to preserve empty runtime folders in git

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/Frontend/src/components/ui/aspect-ratio.jsx

@@ -0,0 +1,3 @@
+import * as AspectRatioPrimitive from "@radix-ui/react-aspect-ratio";
+const AspectRatio = AspectRatioPrimitive.Root;
+export { AspectRatio };