feat(launcher): add quick mirror/extend toggle in left menu

Always visible in launcher menu, disabled outside native mode, with title text and preview-note messaging.

src/routes/events/[event_id]/(launcher)/menu_launcher_controls.svelte

@@ -18,16 +18,29 @@
  *   theme mode without hunting through the system menu or requiring admin access.
  */
 
-import { Moon, Sun, Eye, EyeOff } from '@lucide/svelte';
+import { Moon, Sun, Eye, EyeOff, Columns2, Copy } from '@lucide/svelte';
 
 import { ae_loc } from '$lib/stores/ae_stores';
 import { events_loc } from '$lib/stores/ae_events_stores';
+import * as native from '$lib/electron/electron_relay';
 
 interface Props {
     log_lvl?: number;
 }
 
 let { log_lvl = $bindable(0) }: Props = $props();
+
+let quick_display_mode = $state<'extend' | 'mirror'>('extend');
+
+const is_native_launcher_mode = $derived(
+    !!$ae_loc.is_native && $events_loc.launcher.app_mode === 'native'
+);
+
+async function set_quick_display_mode(mode: 'extend' | 'mirror') {
+    if (!is_native_launcher_mode) return;
+    const res = await native.set_display_layout({ mode });
+    if (res?.success) quick_display_mode = mode;
+}
 </script>
 
 <div class="flex w-full max-w-full flex-col items-center justify-center gap-1">
@@ -152,4 +165,51 @@ let { log_lvl = $bindable(0) }: Props = $props();
             {/if}
         </button>
     </div>
+
+    <!-- ── Quick display mode controls — always visible (native-only action) ── -->
+    <div class="flex w-full max-w-full flex-row items-center justify-center gap-1">
+        <button
+            type="button"
+            onclick={() => set_quick_display_mode('extend')}
+            disabled={!is_native_launcher_mode}
+            class="
+                btn btn-sm group w-1/2 max-w-1/2 text-xs transition-all
+                border-2
+            "
+            class:border-primary-500={quick_display_mode === 'extend'}
+            class:preset-tonal-primary={quick_display_mode === 'extend'}
+            class:border-surface-400={quick_display_mode !== 'extend'}
+            class:preset-tonal-surface={quick_display_mode !== 'extend'}
+            title="Set display layout to Extend (separate laptop and projector screens).">
+            <Columns2 size="0.9em" class="m-1 inline-block" />
+            <span class="hidden group-hover:inline-block">Display: Extend</span>
+            <span class="group-hover:hidden">Extend</span>
+        </button>
+
+        <button
+            type="button"
+            onclick={() => set_quick_display_mode('mirror')}
+            disabled={!is_native_launcher_mode}
+            class="
+                btn btn-sm group w-1/2 max-w-1/2 text-xs transition-all
+                border-2
+            "
+            class:border-warning-500={quick_display_mode === 'mirror'}
+            class:preset-tonal-warning={quick_display_mode === 'mirror'}
+            class:border-surface-400={quick_display_mode !== 'mirror'}
+            class:preset-tonal-surface={quick_display_mode !== 'mirror'}
+            title="Set display layout to Mirror (same content on laptop and projector).">
+            <Copy size="0.9em" class="m-1 inline-block" />
+            <span class="hidden group-hover:inline-block">Display: Mirror</span>
+            <span class="group-hover:hidden">Mirror</span>
+        </button>
+    </div>
+
+    {#if !is_native_launcher_mode}
+        <div
+            class="text-[10px] leading-tight opacity-70 text-center px-2"
+            title="Shown here as a visual preview. Active in native app mode in the session room.">
+            Display toggle shown as an example preview. Active in native app mode in the session room.
+        </div>
+    {/if}
 </div>