✨(frontend) integrate posthog analytics

We integrate posthog, it will help us to track
user behavior and improve the product.
We get the configuration from the backend config
endpoint.

src/frontend/apps/impress/package.json

@@ -31,6 +31,7 @@
     "lodash": "4.17.21",
     "luxon": "3.5.0",
     "next": "15.1.3",
+    "posthog-js": "1.204.0",
     "react": "*",
     "react-aria-components": "1.5.0",
     "react-dom": "*",