feat: Add service worker with offline support and route caching to web dashboard

- Add offline.html fallback page with gradient background, centered container, and retry button
- Add sw.js service worker with telecom-dashboard-v1 cache for dashboard routes
- Add install event handler caching /, /login, /dashboard, /services, /monitoring, /deploy, /plugins, /automation, /chaos, /billing, and /config routes
- Add fetch event handler with cache-first strategy and offline.html fallback
- Add activate event

apps/web-dashboard/public/offline.html

@@ -0,0 +1,59 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Offline - Telecom Dashboard</title>
+    <style>
+        body {
+            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
+            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
+            display: flex;
+            justify-content: center;
+            align-items: center;
+            height: 100vh;
+            margin: 0;
+            color: white;
+        }
+        .container {
+            text-align: center;
+            padding: 2rem;
+            background: rgba(255, 255, 255, 0.1);
+            border-radius: 1rem;
+            backdrop-filter: blur(10px);
+            max-width: 500px;
+        }
+        h1 {
+            font-size: 2rem;
+            margin-bottom: 1rem;
+        }
+        p {
+            font-size: 1.1rem;
+            margin-bottom: 1.5rem;
+            opacity: 0.9;
+        }
+        button {
+            background: white;
+            color: #667eea;
+            border: none;
+            padding: 0.75rem 1.5rem;
+            border-radius: 0.5rem;
+            font-size: 1rem;
+            cursor: pointer;
+            font-weight: 600;
+            transition: transform 0.2s, box-shadow 0.2s;
+        }
+        button:hover {
+            transform: translateY(-2px);
+            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
+        }
+    </style>
+</head>
+<body>
+    <div class="container">
+        <h1>You're Offline</h1>
+        <p>Check your internet connection and try again.</p>
+        <button onclick="window.location.reload()">Retry</button>
+    </div>
+</body>
+</html>

apps/web-dashboard/public/sw.js

@@ -0,0 +1,51 @@
+const CACHE_NAME = 'telecom-dashboard-v1';
+const urlsToCache = [
+  '/',
+  '/login',
+  '/dashboard',
+  '/services',
+  '/monitoring',
+  '/deploy',
+  '/plugins',
+  '/automation',
+  '/chaos',
+  '/billing',
+  '/config',
+];
+
+self.addEventListener('install', (event) => {
+  event.waitUntil(
+    caches.open(CACHE_NAME)
+      .then((cache) => {
+        return cache.addAll(urlsToCache);
+      })
+  );
+});
+
+self.addEventListener('fetch', (event) => {
+  event.respondWith(
+    caches.match(event.request)
+      .then((response) => {
+        if (response) {
+          return response;
+        }
+        return fetch(event.request).catch(() => {
+          return caches.match('/offline.html');
+        });
+      })
+  );
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+    caches.keys().then((cacheNames) => {
+      return Promise.all(
+        cacheNames.map((cacheName) => {
+          if (cacheName !== CACHE_NAME) {
+            return caches.delete(cacheName);
+          }
+        })
+      );
+    })
+  );
+});

apps/web-dashboard/src/app/layout.tsx

@@ -4,6 +4,7 @@ import "./globals.css";
 import { cn } from "@/lib/utils";
 import { Sidebar } from "@/components/sidebar";
 import { Providers } from "./providers";
+import { ServiceWorkerRegistration } from "@/components/service-worker-registration";
 
 const inter = Inter({ subsets: ["latin"], variable: "--font-sans" });
 
@@ -34,6 +35,7 @@ export default function RootLayout({
     >
       <body className="min-h-full flex">
         <Providers>
+          <ServiceWorkerRegistration />
           <Sidebar />
           <main className="flex-1 overflow-auto">{children}</main>
         </Providers>

apps/web-dashboard/src/components/service-worker-registration.tsx

@@ -0,0 +1,22 @@
+"use client";
+
+import { useEffect } from "react";
+
+export function ServiceWorkerRegistration() {
+  useEffect(() => {
+    if ("serviceWorker" in navigator && process.env.NEXT_PUBLIC_ENABLE_SW === "true") {
+      window.addEventListener("load", () => {
+        navigator.serviceWorker
+          .register("/sw.js")
+          .then((registration) => {
+            console.log("Service Worker registered: ", registration);
+          })
+          .catch((registrationError) => {
+            console.log("Service Worker registration failed: ", registrationError);
+          });
+      });
+    }
+  }, []);
+
+  return null;
+}