Spread fleet replicas across extra machines and show message RTT percentiles

machines.json plus Add-machine UI place copies on the least-loaded host.
Monitor samples processing RTT and displays min, avg, p50, and p90 for
capacity planning. Remote hosts run src/agent.js.

packages/verae-fleet/machines.json

@@ -0,0 +1,30 @@
+{
+  "machines": [
+    {
+      "id": "local",
+      "title": "Control plane (this host)",
+      "kind": "local",
+      "host": "127.0.0.1",
+      "enabled": true,
+      "capacity": 32,
+      "roles": ["*"]
+    },
+    {
+      "id": "ns1",
+      "title": "NS1.GEORGELAMBERT.ORG",
+      "kind": "agent",
+      "host": "70.88.205.138",
+      "agentPort": 3851,
+      "enabled": false,
+      "capacity": 24,
+      "roles": [
+        "tree-node",
+        "archive-worm",
+        "archive-aggregator",
+        "job-poller",
+        "webhook-deliver"
+      ],
+      "notes": "Run `node src/agent.js` on NS1, then enable this machine to spread tree-node / WORM capacity. Agent port is loopback-plus-SSH-tunnel or private LAN — do not publish NATS."
+    }
+  ]
+}