Fix layer visibility toggle reactivity

- Use $set() for array property updates in Alpine.js
- Change tintRed to use x-model for proper reactivity

tools/ora_editor/templates/editor.html

@@ -115,8 +115,10 @@
             },
 
             async toggleVisibility(layerName, visible) {
-                const layer = this.layers.find(l => l.name === layerName);
-                if (layer) layer.visible = visible;
+                const idx = this.layers.findIndex(l => l.name === layerName);
+                if (idx >= 0) {
+                    this.$set(this.layers[idx], 'visible', visible);
+                }
                 
                 await fetch('/api/layer/visibility', {
                     method: 'POST',
@@ -548,8 +550,7 @@
                             <span class="flex-1 text-sm truncate" x-text="layer.name"></span>
                             <input 
                                 type="checkbox"
-                                :checked="layer.tintRed || false"
-                                @change="layer.tintRed = $event.target.checked"
+                                x-model="layer.tintRed"
                                 class="w-4 h-4 rounded"
                                 title="Tint red for preview"
                             >