Implement layer visibility toggle; log export color range

- Wire MenuAction::ToggleLayerVisibility (was a stub) to flip the active
  layer's `visible` flag via SetLayerPropertiesAction (undoable). This is
  what the SVG-export visibility fix depends on, and the "Hide/Show Layer"
  menu item now works.
- Log the resolved color range in the zero-copy H.264 path to diagnose
  whether `full_range` reaches the encoder (the VAAPI driver may still omit
  the SPS VUI full_range flag).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lightningbeam-ui/lightningbeam-editor/src/export/mod.rs

@@ -921,6 +921,8 @@ impl ExportOrchestrator {
         let bitrate = settings.quality.bitrate_kbps();
         let fr = framerate.round() as i32;
         let full = settings.color_range.is_full();
+        println!("🎬 [EXPORT] zero-copy H.264 color range: {} (full_range={})",
+            settings.color_range.name(), full);
         let on_shared_device = shared_device.is_some();
         // Prefer the shared device → decode→composite→encode stay GPU-resident on one device.
         // Without it, the encoder builds its own device (decode still downloads to CPU per Step 1's

lightningbeam-ui/lightningbeam-editor/src/main.rs

@@ -3727,8 +3727,21 @@ impl EditorApp {
                 // TODO: Implement delete layer
             }
             MenuAction::ToggleLayerVisibility => {
-                println!("Menu: Toggle Layer Visibility");
+                use lightningbeam_core::actions::{SetLayerPropertiesAction, set_layer_properties::LayerProperty};
-                // TODO: Implement toggle layer visibility
+                use lightningbeam_core::layer::LayerTrait;
+                if let Some(layer_id) = self.active_layer_id {
+                    let cur = self.action_executor.document()
+                        .get_layer(&layer_id)
+                        .map(|l| l.visible());
+                    if let Some(cur) = cur {
+                        let action = SetLayerPropertiesAction::new(layer_id, LayerProperty::Visible(!cur));
+                        if let Err(e) = self.action_executor.execute(Box::new(action)) {
+                            eprintln!("Toggle layer visibility: {}", e);
+                        }
+                    }
+                } else {
+                    println!("Toggle Layer Visibility: no active layer");
+                }
             }
             MenuAction::ShowMasterTrack => {
                 // Toggle show_master_track on all Timeline pane instances