Fix issue with QR code login and caching. Update README

src/static/app.js

@@ -215,15 +215,18 @@ document.getElementById("logout-btn").addEventListener("click", () => {
       headers: { "Content-Type": "application/json" },
       body: JSON.stringify({ code: k.toUpperCase() }),
     })
-      .then(res => res.ok ? res.json() : Promise.reject())
+      .then(res => res.ok ? res.json() : res.json().then(j => Promise.reject(j.detail || "Invalid keypass")))
       .then(data => {
         saveToken(data.token);
         showGatesView();
         loadGates();
       })
-      .catch(() => {
+      .catch(msg => {
         clearToken();
         showLogin();
+        const errEl = document.getElementById("login-error");
+        errEl.textContent = typeof msg === "string" ? msg : "QR code login failed";
+        errEl.classList.remove("hidden");
       });
     return;
   }

src/static/sw.js

@@ -1,6 +1,6 @@
 /* Service worker - Lagomare Gates */
 const CACHE = "lagomare-gates-v1";
-const PRECACHE = ["/", "/static/style.css", "/static/app.js", "/static/logo.svg", "/static/mobile_icon.png", "/manifest.json"];
+const PRECACHE = ["/static/style.css", "/static/app.js", "/static/logo.svg", "/static/mobile_icon.png", "/manifest.json"];
 
 self.addEventListener("install", event => {
   event.waitUntil(
@@ -20,6 +20,10 @@ self.addEventListener("fetch", event => {
   // Let API calls always go to the network
   if (event.request.url.includes("/api/")) return;
 
+  // Navigation requests (page loads, QR code opens) must always hit the network
+  // so query parameters like ?k=CODE are preserved for app.js
+  if (event.request.mode === "navigate") return;
+
   event.respondWith(
     caches.match(event.request).then(cached => cached || fetch(event.request))
   );