1. Sign up free at app.posthog.com (1M events/month free)
2. Create a project, copy the Project API Key (phc_…) → set POSTHOG_KEY in .env
3. Go to Settings → Personal API Keys → create one → set POSTHOG_PERSONAL_API_KEY
4. Go to Settings → Project ID → set POSTHOG_PROJECT_ID
5. Run docker compose up -d nxt-analytics nxt-media nxt-frontend nxt-api