Update StatusBox to display app version and adjust refresh intervals

Add a new element in StatusBox.vue to show the application version. Update the refresh interval for status display from every 0.5 seconds to every 1 second for improved performance. Increment mobile app version to 0.8.0-alpha8 and version code to 9. Introduce new VersionScreen in the mobile app for displaying version information, and update navigation and mock data accordingly.

frontend/src/components/StatusBox.vue

@@ -29,6 +29,7 @@
         <span class="value" v-if="value !== null">{{ value || '—' }}</span>
       </div>
     </div>
+    <div class="status-version">TimeClock v{{ appVersion }}</div>
   </div>
   <div class="status-box loading" v-else>
     Lädt…
@@ -40,8 +41,10 @@ import { onMounted, onBeforeUnmount, ref, computed } from 'vue'
 import { useTimeStore } from '../stores/timeStore'
 import { useAuthStore } from '../stores/authStore'
 import { API_BASE_URL } from '@/config/api'
+import { APP_VERSION } from '@/config/version'
 
 const API_URL = API_BASE_URL
+const appVersion = APP_VERSION
 const timeStore = useTimeStore()
 const authStore = useAuthStore()
 const stats = ref({})
@@ -389,11 +392,11 @@ onMounted(async () => {
     await refreshStatusData()
   }, 60000)
   
-  // Anzeige 2x pro Sekunde aktualisieren (nur Berechnung, keine Server-Requests)
+  // Anzeige jede Sekunde aktualisieren (nur Berechnung, keine Server-Requests)
   displayUpdateInterval = setInterval(() => {
     updateCurrentlyWorkedTime()
     updateOpenTime()
-  }, 500)
+  }, 1000)
   
   // Event-Listener für Login
   window.addEventListener('login-completed', handleLoginCompleted)
@@ -584,4 +587,13 @@ const displayRows = computed(() => {
   color: #000; 
   font-weight: 500; 
 }
+
+.status-version {
+  margin-top: 8px;
+  padding-top: 6px;
+  border-top: 1px solid #e8e8e8;
+  text-align: center;
+  font-size: 11px;
+  color: #888;
+}
 </style>

frontend/src/config/version.js

@@ -0,0 +1,2 @@
+/** Sichtbare Web-App-Version (synchron mit package.json). */
+export const APP_VERSION = '3.0.0'