Replace GCS endpoints with Hetzner regional, change interval to 3s

GCS locational endpoints were too slow (>1500ms). Replace with 6
Hetzner speed test servers (Nuremberg DE, Falkenstein DE, Helsinki
FI, Ashburn VA-US, Hillsboro OR-US, Singapore SG) which are genuine
per-DC HTTPS endpoints. Bump update interval from 2s to 3s.

src/main.js

@@ -8,7 +8,7 @@ import "./styles.css";
 // display their real value in the latency figure. The history buffer holds
 // maxHistoryPoints samples (historyDuration / updateInterval).
 const CONFIG = Object.freeze({
-    updateInterval: 2000,
+    updateInterval: 3000,
     historyDuration: 300,
     requestTimeout: 1500,
     maxLatency: 1500,
@@ -64,22 +64,30 @@ const WAN_HOSTS = [
         name: "S3 sa-east-1 (São Paulo)",
         url: "https://s3.sa-east-1.amazonaws.com",
     },
-    // GCS locational endpoints — compare GCP routing vs AWS per-continent
+    // Hetzner regional speed test servers — genuine per-DC endpoints
     {
-        name: "GCS us-cent1 (Iowa)",
-        url: "https://storage.us-central1.rep.googleapis.com",
+        name: "Hetzner nbg1 (Nuremberg DE)",
+        url: "https://nbg1-speed.hetzner.com",
     },
     {
-        name: "GCS eu-west1 (Belgium)",
-        url: "https://storage.europe-west1.rep.googleapis.com",
+        name: "Hetzner fsn1 (Falkenstein DE)",
+        url: "https://fsn1-speed.hetzner.com",
     },
     {
-        name: "GCS asia-se1 (Singapore)",
-        url: "https://storage.asia-southeast1.rep.googleapis.com",
+        name: "Hetzner hel1 (Helsinki FI)",
+        url: "https://hel1-speed.hetzner.com",
     },
     {
-        name: "GCS aus-se1 (Sydney)",
-        url: "https://storage.australia-southeast1.rep.googleapis.com",
+        name: "Hetzner ash (Ashburn VA-US)",
+        url: "https://ash-speed.hetzner.com",
+    },
+    {
+        name: "Hetzner hil (Hillsboro OR-US)",
+        url: "https://hil-speed.hetzner.com",
+    },
+    {
+        name: "Hetzner sin (Singapore SG)",
+        url: "https://sin-speed.hetzner.com",
     },
 ];