heavily simplify server and app content. unify styling

app/composables/useAutoCloseLiveSession.js

@@ -0,0 +1,12 @@
+/** Auto-closes selectedCamera when the selected live session disappears from liveSessions. */
+export function useAutoCloseLiveSession(selectedCamera, liveSessions) {
+  watch(
+    [() => selectedCamera.value, () => liveSessions.value],
+    ([sel, sessions]) => {
+      if (!sel || typeof sel.hasStream === 'undefined') return
+      const stillActive = (sessions ?? []).some(s => s.id === sel.id)
+      if (!stillActive) selectedCamera.value = null
+    },
+    { deep: true },
+  )
+}