feat: add LoadingOverlay component with contextual busy messages for async operations across cluster sync, firewall preview/apply, IPAM discovery/export, node agent installer, and policy compilation

Add LoadingOverlay component with spinner, customizable title/message, and backdrop blur styling, implement busy state tracking with setBusyMessage in Clusters/FirewallPreview/Ipam/Nodes/Policies pages, wrap async operations (cluster test/sync, firewall preview/apply, IPAM discover/export CSV, node agent installer

frontend/src/pages/Clusters.tsx

@@ -5,6 +5,7 @@ import { Cable, Pencil, Plus, RefreshCcw, Server, Trash2 } from "lucide-react";
 import { api, Cluster } from "../api/client";
 import { DataTable } from "../components/DataTable";
 import { buttonClass, Field, iconButtonClass, inputClass, selectClass } from "../components/FormControls";
+import { LoadingOverlay } from "../components/LoadingOverlay";
 import { Modal } from "../components/Modal";
 import { PageHeader } from "../components/PageHeader";
 
@@ -24,6 +25,7 @@ export function Clusters() {
   const [result, setResult] = useState("");
   const [open, setOpen] = useState(false);
   const [editing, setEditing] = useState<Cluster | null>(null);
+  const [busyMessage, setBusyMessage] = useState("");
 
   const save = useMutation({
     mutationFn: () => {
@@ -69,9 +71,14 @@ export function Clusters() {
   }
 
   async function action(cluster: Cluster, kind: "test" | "sync") {
-    const data = await api<Record<string, unknown>>(`/clusters/${cluster.id}/${kind}`, { method: "POST" });
-    setResult(JSON.stringify(data, null, 2));
-    await queryClient.invalidateQueries({ queryKey: ["clusters"] });
+    setBusyMessage(kind === "sync" ? `Syncing inventory for ${cluster.name}...` : `Testing connection to ${cluster.name}...`);
+    try {
+      const data = await api<Record<string, unknown>>(`/clusters/${cluster.id}/${kind}`, { method: "POST" });
+      setResult(JSON.stringify(data, null, 2));
+      await queryClient.invalidateQueries({ queryKey: ["clusters"] });
+    } finally {
+      setBusyMessage("");
+    }
   }
 
   function deleteCluster(cluster: Cluster) {
@@ -83,6 +90,7 @@ export function Clusters() {
   return (
     <>
       <PageHeader title="Clusters" subtitle="Register, test, and sync Proxmox or demo providers." />
+      <LoadingOverlay open={Boolean(busyMessage)} message={busyMessage} />
       <div className="space-y-4">
         <button className={buttonClass} onClick={addCluster}><Plus size={16} /> Add Cluster</button>
         <Modal title={editing ? "Edit Cluster" : "Add Cluster"} open={open} onClose={() => setOpen(false)}>

frontend/src/pages/FirewallPreview.tsx

@@ -4,6 +4,7 @@ import { useState } from "react";
 
 import { api, Cluster, Policy } from "../api/client";
 import { buttonClass, Field, secondaryButtonClass, selectClass } from "../components/FormControls";
+import { LoadingOverlay } from "../components/LoadingOverlay";
 import { PageHeader } from "../components/PageHeader";
 
 export function FirewallPreview() {
@@ -28,10 +29,18 @@ export function FirewallPreview() {
       }),
   });
   const selectedPolicyId = policyId || policies.data?.[0]?.id || "";
+  const busyMessage = preview.isPending
+    ? "Generating firewall preview..."
+    : apply.isPending
+      ? dryRun
+        ? "Running dry apply..."
+        : "Applying firewall rules..."
+      : "";
 
   return (
     <>
       <PageHeader title="Firewall Preview" subtitle="Compile policies into provider-specific rules before any apply operation." />
+      <LoadingOverlay open={Boolean(busyMessage)} message={busyMessage} />
       <div className="grid gap-4 lg:grid-cols-[360px_1fr]">
         <section className="rounded-md border border-border bg-panel p-4">
           <div className="grid gap-3">

frontend/src/pages/Ipam.tsx

@@ -5,6 +5,7 @@ import { Database, Download, Plus } from "lucide-react";
 import { api, authorizedFetch, IpAddress, Network, Subnet } from "../api/client";
 import { DataTable } from "../components/DataTable";
 import { buttonClass, Field, inputClass, secondaryButtonClass, selectClass } from "../components/FormControls";
+import { LoadingOverlay } from "../components/LoadingOverlay";
 import { Modal } from "../components/Modal";
 import { PageHeader } from "../components/PageHeader";
 
@@ -18,6 +19,7 @@ export function Ipam() {
   const [ipForm, setIpForm] = useState({ subnet_id: "", address: "10.50.0.20", status: "reserved", note: "" });
   const [subnetOpen, setSubnetOpen] = useState(false);
   const [ipOpen, setIpOpen] = useState(false);
+  const [busyMessage, setBusyMessage] = useState("");
 
   const createSubnet = useMutation({
     mutationFn: () => api<Subnet>("/ipam/subnets", { method: "POST", body: JSON.stringify({ ...subnetForm, network_id: subnetForm.network_id || networks.data?.[0]?.id }) }),
@@ -49,17 +51,23 @@ export function Ipam() {
   }
 
   async function exportCsv() {
-    const response = await authorizedFetch("/ipam/export.csv");
-    const blob = await response.blob();
-    const url = URL.createObjectURL(blob);
-    const link = document.createElement("a");
-    link.href = url;
-    link.download = "nexafabric-ipam.csv";
-    link.click();
-    URL.revokeObjectURL(url);
+    setBusyMessage("Preparing IPAM export...");
+    try {
+      const response = await authorizedFetch("/ipam/export.csv");
+      const blob = await response.blob();
+      const url = URL.createObjectURL(blob);
+      const link = document.createElement("a");
+      link.href = url;
+      link.download = "nexafabric-ipam.csv";
+      link.click();
+      URL.revokeObjectURL(url);
+    } finally {
+      setBusyMessage("");
+    }
   }
 
   async function discoverIpam() {
+    setBusyMessage("Discovering IP addresses from Proxmox...");
     try {
       const result = await api<{ imported: number; removed: number; errors: Array<Record<string, unknown>> }>("/ipam/discover", { method: "POST" });
       setMessage(`Discovery imported ${result.imported} IP addresses and removed ${result.removed} container bridge entries${result.errors.length ? " with errors" : ""}.`);
@@ -67,12 +75,15 @@ export function Ipam() {
       await queryClient.invalidateQueries({ queryKey: ["addresses"] });
     } catch (error) {
       setMessage(error instanceof Error ? error.message : "IPAM discovery failed.");
+    } finally {
+      setBusyMessage("");
     }
   }
 
   return (
     <>
       <PageHeader title="IPAM" subtitle="Manage subnets, reservations, assignments, conflicts, and export state." />
+      <LoadingOverlay open={Boolean(busyMessage)} message={busyMessage} />
       <div className="space-y-4">
         <div className="flex flex-wrap gap-2">
           <button className={buttonClass} onClick={() => setSubnetOpen(true)}><Plus size={16} /> Add Subnet</button>

frontend/src/pages/Nodes.tsx

@@ -5,6 +5,7 @@ import { useState } from "react";
 import { AgentInstallInfo, api, Node } from "../api/client";
 import { DataTable } from "../components/DataTable";
 import { iconButtonClass, secondaryButtonClass } from "../components/FormControls";
+import { LoadingOverlay } from "../components/LoadingOverlay";
 import { Modal } from "../components/Modal";
 import { PageHeader } from "../components/PageHeader";
 
@@ -47,6 +48,7 @@ export function Nodes() {
   return (
     <>
       <PageHeader title="Nodes" subtitle="Cluster nodes, capacity, health, and NexaFabric agent enrollment." />
+      <LoadingOverlay open={installInfo.isPending} message="Generating node agent installer..." />
       {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 ? (

frontend/src/pages/Policies.tsx

@@ -5,6 +5,7 @@ import { Eye, GitBranch, Pencil, Play, Plus, Trash2 } from "lucide-react";
 import { api, Policy, Project, ServiceCatalogItem } from "../api/client";
 import { DataTable } from "../components/DataTable";
 import { buttonClass, Field, iconButtonClass, inputClass, selectClass } from "../components/FormControls";
+import { LoadingOverlay } from "../components/LoadingOverlay";
 import { Modal } from "../components/Modal";
 import { PageHeader } from "../components/PageHeader";
 
@@ -45,6 +46,7 @@ export function Policies() {
   const [open, setOpen] = useState(false);
   const [editing, setEditing] = useState<Policy | null>(null);
   const [form, setForm] = useState(defaultPolicyForm);
+  const [busyMessage, setBusyMessage] = useState("");
 
   const save = useMutation({
     mutationFn: () => {
@@ -85,14 +87,24 @@ export function Policies() {
   }
 
   async function compile(policy: Policy) {
-    const data = await api<Policy>(`/policies/${policy.id}/compile`, { method: "POST" });
-    setPreview(JSON.stringify(data.last_compiled, null, 2));
-    await queryClient.invalidateQueries({ queryKey: ["policies"] });
+    setBusyMessage(`Compiling ${policy.name}...`);
+    try {
+      const data = await api<Policy>(`/policies/${policy.id}/compile`, { method: "POST" });
+      setPreview(JSON.stringify(data.last_compiled, null, 2));
+      await queryClient.invalidateQueries({ queryKey: ["policies"] });
+    } finally {
+      setBusyMessage("");
+    }
   }
 
   async function firewallPreview(policy: Policy) {
-    const data = await api<Record<string, unknown>>(`/firewall/preview/${policy.id}`, { method: "POST" });
-    setPreview(JSON.stringify(data, null, 2));
+    setBusyMessage(`Generating preview for ${policy.name}...`);
+    try {
+      const data = await api<Record<string, unknown>>(`/firewall/preview/${policy.id}`, { method: "POST" });
+      setPreview(JSON.stringify(data, null, 2));
+    } finally {
+      setBusyMessage("");
+    }
   }
 
   function addPolicy() {
@@ -140,6 +152,7 @@ export function Policies() {
   return (
     <>
       <PageHeader title="Policies" subtitle="Create versioned microsegmentation policies and compile firewall previews." />
+      <LoadingOverlay open={Boolean(busyMessage)} message={busyMessage} />
       <div className="space-y-4">
         <button className={buttonClass} onClick={addPolicy}><Plus size={16} /> Add Policy</button>
         <Modal title={editing ? "Edit Policy" : "Add Policy"} open={open} onClose={() => setOpen(false)}>