Cely analytics + watchdog stack bezi na existujucej infrastrukture bez externych zavislosti (okrem SendGrid pre emaily).

ASCII diagram
Frontend (Next.js)                    Server (162.55.89.156)
+----------------------+              +----------------------------+
|  useAnalytics() hook |--POST------->|  /api/analytics            |
|  - buffer 50 events  |              |  - visitor upsert          |
|  - flush 10s / 20+   |              |  - session create/update   |
|  - keepalive on hide  |              |  - batch event insert      |
|                      |              |  - heatmap aggregation     |
|  Stats page /v3/stats|--GET-------->|  /api/analytics/stats      |
|                      |              |  (admin auth required)     |
|  Watch UI            |--POST------->|  /api/watches              |
|                      |              |  - CRUD watches            |
|                      |              |  /api/watches/match        |
|                      |              |  - geo matching engine     |
+----------------------+              +----------+-----------------+
                                                 |
                                      +----------v-----------------+
                                      |  PostgreSQL (portal-db)    |
                                      |  analytics_visitors        |
                                      |  analytics_sessions        |
                                      |  analytics_events          |
                                      |  analytics_heatmap         |
                                      |  analytics_watches         |
                                      |  watch_notifications       |
                                      +----------+-----------------+
                                                 |
                                      +----------v-----------------+
                                      |  Grafana (:3002)           |
                                      |  - auto-provisioned PG     |
                                      |  - internal dashboards     |
                                      +----------------------------+

          Email flow (buduce):
          +---------------------------------------------+
          |  Cron/Trigger -> Match -> Puppeteer screenshot |
          |  -> /internal/watch-map -> PNG -> SendGrid API  |
          +---------------------------------------------+