feat: initial scaffold with Event Management, Participant Management, and Budget Management

- Express backend with JWT auth, PostgreSQL, full CRUD APIs
- React + Vite + TailwindCSS frontend with RTL Hebrew UI
- Event Creation & Management (create/edit/delete/list events)
- Participant Management (add/edit/delete/status tracking per event)
- Budget Management (income/expense tracking with balance summary)
- Docker Compose setup with PostgreSQL
- /health endpoint with commit-id and DB status

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

client/postcss.config.js

@@ -0,0 +1,6 @@
+export default {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}