Layout + SW: Tab-Leiste sichtbar + kein veralteter Cache

- main-content padding-top auf calc(var(--nav-h) + 0.75rem) erhöht
  damit die Tab-Leiste (Radio/Focus/Podcasts/Books) sicher unterhalb
  der fixed Navbar liegt — auf Desktop und Mobile
- SW v10: sendet SW_ACTIVATED an alle offenen Tabs wenn ein neuer SW
  übernimmt; app.js lädt daraufhin neu (außer wenn ein Buch geöffnet
  ist) — verhindert dass der Browser eine uralte HTTP-gecachte Version
  ausliefert

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/css/app.css

@@ -149,8 +149,8 @@ a:hover {
 .main-content {
   max-width: 1100px;
   margin: 0 auto;
-  padding: 1rem 1.5rem calc(var(--bar-h) + 2rem);
-  height: calc(100% - var(--nav-h));
+  padding: calc(var(--nav-h) + 0.75rem) 1.5rem calc(var(--bar-h) + 2rem);
+  height: 100%;
   overflow-y: auto;
 }
 
@@ -736,7 +736,7 @@ a:hover {
 
 @media (max-width: 600px) {
   .main-content {
-    padding: 0.75rem 0.75rem calc(var(--bar-h) + 1.5rem);
+    padding: calc(var(--nav-h) + 0.5rem) 0.75rem calc(var(--bar-h) + 1.5rem);
   }
 
   .now-playing-bar {

static/js/app.js

@@ -2213,6 +2213,13 @@ if ('serviceWorker' in navigator) {
       console.warn('Service worker registration failed:', err);
     });
   });
+  // When a new SW activates it sends SW_ACTIVATED — reload to get fresh assets,
+  // but only if the reader isn't open (would interrupt reading).
+  navigator.serviceWorker.addEventListener('message', e => {
+    if (e.data?.type === 'SW_ACTIVATED' && !currentBookId) {
+      window.location.reload();
+    }
+  });
 }
 
 // ---------------------------------------------------------------------------

static/js/sw.js

@@ -2,7 +2,7 @@
  * diora service worker — caches the app shell for offline use.
  */
 
-const CACHE = 'diora-v9';
+const CACHE = 'diora-v10';
 const PODCAST_CACHE = 'diora-podcast-v1';
 const SHELL = [
   '/static/css/app.css',
@@ -31,6 +31,13 @@ self.addEventListener('activate', function (event) {
       );
     }).then(function () {
       return self.clients.claim();
+    }).then(function () {
+      // Tell all open tabs to reload so they get the latest cached assets
+      return self.clients.matchAll({type: 'window'}).then(function (clients) {
+        clients.forEach(function (client) {
+          client.postMessage({type: 'SW_ACTIVATED'});
+        });
+      });
     })
   );
 });