Translate UI to English and add PWA support

app/web/static/js/service-worker.js

@@ -0,0 +1,72 @@
+const CACHE_NAME = "llm-monitor-v1";
+const APP_SHELL = [
+  "/",
+  "/models-running",
+  "/models-available",
+  "/static/css/output.css",
+  "/static/js/app.js",
+  "/static/js/models-running.js",
+  "/static/js/data-sync.worker.js",
+  "/static/js/pwa-register.js",
+  "/manifest.webmanifest",
+  "/favicon.ico"
+];
+
+self.addEventListener("install", (event) => {
+  event.waitUntil(
+    caches.open(CACHE_NAME).then((cache) => cache.addAll(APP_SHELL))
+  );
+  self.skipWaiting();
+});
+
+self.addEventListener("activate", (event) => {
+  event.waitUntil(
+    caches.keys().then((keys) =>
+      Promise.all(
+        keys.filter((key) => key !== CACHE_NAME).map((key) => caches.delete(key))
+      )
+    )
+  );
+  self.clients.claim();
+});
+
+self.addEventListener("fetch", (event) => {
+  if (event.request.method !== "GET") {
+    return;
+  }
+
+  const requestUrl = new URL(event.request.url);
+  const isApiRequest = requestUrl.pathname.startsWith("/api/");
+
+  if (isApiRequest) {
+    event.respondWith(
+      fetch(event.request).catch(() =>
+        new Response(JSON.stringify({ detail: "Offline" }), {
+          status: 503,
+          headers: { "Content-Type": "application/json" }
+        })
+      )
+    );
+    return;
+  }
+
+  event.respondWith(
+    caches.match(event.request).then((cached) => {
+      if (cached) {
+        return cached;
+      }
+
+      return fetch(event.request)
+        .then((response) => {
+          if (!response || response.status !== 200 || response.type !== "basic") {
+            return response;
+          }
+
+          const responseClone = response.clone();
+          caches.open(CACHE_NAME).then((cache) => cache.put(event.request, responseClone));
+          return response;
+        })
+        .catch(() => caches.match("/models-running"));
+    })
+  );
+});