Add graph telemetry and remote signer login

.env.example

@@ -13,10 +13,10 @@ LOG_LEVEL=info
 # STATIC_DIR=
 
 # ---- Datum gateway (the Umbrel app we're polling) ----
-# Reachable internally inside Umbrel's docker network. From your LAN it's also
-# at http://192.168.1.191:21000 but that path goes through umbrelOS auth.
-# Inside the Umbrel docker network, use the Datum service hostname directly.
-DATUM_URL=http://10.21.0.11:21000
+# Inside the Umbrel docker network, use Datum's service hostname directly.
+# If you run the API outside that Docker network, override this with a hostname
+# or IP address reachable from that process.
+DATUM_URL=http://datum:21000
 DATUM_ADMIN_USER=admin
 DATUM_ADMIN_PASSWORD=
 # How often to scrape /clients (ms). Datum updates per-worker hashrate every