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>

.gitignore

@@ -1 +1,22 @@
 node_modules
+
+# Build cache
+.turbo/
+
+# Generated TypeScript declarations
+**/*.d.ts
+**/*.d.ts.map
+
+# Runtime / sensitive backend data (keep folders, ignore contents)
+apps/Backend/backups/*
+apps/Backend/chat-history/*
+apps/Backend/uploads/*
+apps/Backend/license.json
+apps/Backend/network-backup-key.json
+apps/SeleniumService/downloads/*
+
+# Keep the folders themselves
+!apps/Backend/backups/.gitkeep
+!apps/Backend/chat-history/.gitkeep
+!apps/Backend/uploads/.gitkeep
+!apps/SeleniumService/downloads/.gitkeep