feat: add node agent system with heartbeat collection, installer generation, and traffic flow telemetry

Add NodeAgent and TrafficFlow models to track agent status and network flows, implement /agents/heartbeat endpoint to receive interface counters, conntrack flows, firewall status, and nftables ruleset hash from agents, add nexafabric-agent.py Python script to collect host telemetry including VM/LXC interface hints via tap/fwbr regex matching, conntrack flow parsing with protocol/state/byte counters, and pve-firewall status checks,

frontend/src/App.tsx

@@ -11,6 +11,7 @@ import { Ipam } from "./pages/Ipam";
 import { ListPage } from "./pages/ListPage";
 import { Login } from "./pages/Login";
 import { Networks } from "./pages/Networks";
+import { Nodes } from "./pages/Nodes";
 import { Policies } from "./pages/Policies";
 import { PolicyDesigner } from "./pages/PolicyDesigner";
 import { SecurityGroups } from "./pages/SecurityGroups";
@@ -46,7 +47,7 @@ function AppRoutes() {
       <Route element={<Layout />}>
         <Route index element={<Dashboard />} />
         <Route path="clusters" element={<Clusters />} />
-        <Route path="nodes" element={<ListPage title="Nodes" subtitle="Cluster nodes, capacity, and health." path="/nodes" columns={[{ key: "name", label: "Name" }, { key: "status", label: "Status" }, { key: "cpu_count", label: "CPU" }, { key: "memory_mb", label: "Memory MB" }]} />} />
+        <Route path="nodes" element={<Nodes />} />
         <Route path="workloads" element={<Workloads />} />
         <Route path="networks" element={<Networks />} />
         <Route path="ipam" element={<Ipam />} />

frontend/src/api/client.ts

@@ -126,6 +126,31 @@ export type Workload = {
   tags: string[];
 };
 
+export type NodeAgent = {
+  node_id: string;
+  status: string;
+  version: string | null;
+  last_seen_at: string | null;
+  install_count: number;
+  last_payload: Record<string, unknown> | null;
+};
+
+export type Node = {
+  id: string;
+  cluster_id: string;
+  name: string;
+  status: string;
+  cpu_count: number;
+  memory_mb: number;
+  agent: NodeAgent | null;
+};
+
+export type AgentInstallInfo = {
+  node_id: string;
+  install_url: string;
+  command: string;
+};
+
 export type WorkloadInsight = {
   workload: Workload;
   assigned_ips: IpAddress[];

frontend/src/pages/Nodes.tsx

@@ -0,0 +1,98 @@
+import { useMutation, useQuery } from "@tanstack/react-query";
+import { Cpu, Copy, RadioTower } from "lucide-react";
+import { useState } from "react";
+
+import { AgentInstallInfo, api, Node } from "../api/client";
+import { DataTable } from "../components/DataTable";
+import { iconButtonClass, secondaryButtonClass } from "../components/FormControls";
+import { Modal } from "../components/Modal";
+import { PageHeader } from "../components/PageHeader";
+
+export function Nodes() {
+  const nodes = useQuery({ queryKey: ["nodes-agents"], queryFn: () => api<Node[]>("/nodes/agents") });
+  const [selectedNode, setSelectedNode] = useState<Node | null>(null);
+  const [copied, setCopied] = useState(false);
+  const installInfo = useMutation({
+    mutationFn: (node: Node) => api<AgentInstallInfo>(`/nodes/${node.id}/agent/install-info`),
+    onSuccess: (_data, node) => {
+      setSelectedNode(node);
+      setCopied(false);
+    },
+  });
+
+  async function copyCommand() {
+    if (!installInfo.data) {
+      return;
+    }
+    await navigator.clipboard.writeText(installInfo.data.command);
+    setCopied(true);
+  }
+
+  return (
+    <>
+      <PageHeader title="Nodes" subtitle="Cluster nodes, capacity, health, and NexaFabric agent enrollment." />
+      {nodes.isLoading ? <div className="rounded-md border border-border bg-panel p-8 text-sm">Loading...</div> : null}
+      {nodes.error ? <div className="rounded-md border border-danger p-4 text-sm text-danger">Failed to load nodes.</div> : null}
+      {!nodes.isLoading && !nodes.error ? (
+        <DataTable
+          rows={(nodes.data ?? []) as unknown as Record<string, unknown>[]}
+          columns={[
+            { key: "name", label: "Name" },
+            { key: "status", label: "Status" },
+            { key: "cpu_count", label: "CPU" },
+            { key: "memory_mb", label: "Memory MB" },
+            {
+              key: "agent",
+              label: "Agent",
+              render: (row) => {
+                const node = row as unknown as Node;
+                return node.agent ? `${node.agent.status}${node.agent.version ? ` · ${node.agent.version}` : ""}` : "not_installed";
+              },
+            },
+            {
+              key: "actions",
+              label: "Actions",
+              render: (row) => {
+                const node = row as unknown as Node;
+                return (
+                  <div className="flex justify-end gap-2">
+                    <button
+                      className={iconButtonClass}
+                      title="Install node agent"
+                      aria-label={`Install agent on ${node.name}`}
+                      onClick={() => installInfo.mutate(node)}
+                    >
+                      <RadioTower size={16} />
+                    </button>
+                  </div>
+                );
+              },
+            },
+          ]}
+        />
+      ) : null}
+      <Modal title="Install Node Agent" open={Boolean(selectedNode)} onClose={() => setSelectedNode(null)}>
+        <div className="space-y-4">
+          <div className="flex items-center gap-2 font-medium">
+            <Cpu size={18} />
+            {selectedNode?.name}
+          </div>
+          <div className="rounded-md border border-border bg-canvas p-3 text-xs text-slate-500 dark:text-slate-400">
+            Run this command as root on the Proxmox node. It installs the agent under <code>/opt/nexafabric-agent</code> and starts a systemd service.
+          </div>
+          <pre className="max-h-48 overflow-auto rounded-md border border-border bg-canvas p-3 text-xs">
+            {installInfo.data?.command ?? "Generating installer..."}
+          </pre>
+          <div className="grid gap-2 text-xs">
+            <span className="text-slate-500 dark:text-slate-400">Installer link</span>
+            <code className="break-all rounded-md border border-border bg-canvas p-3">{installInfo.data?.install_url ?? ""}</code>
+          </div>
+          <button className={secondaryButtonClass} disabled={!installInfo.data} onClick={copyCommand}>
+            <Copy size={16} />
+            {copied ? "Copied" : "Copy Command"}
+          </button>
+        </div>
+      </Modal>
+    </>
+  );
+}