fix(zoom): 批量建议缩放后不再抢占选中态，避免导出面板被隐藏

handleZoomSuggested 每加一个建议缩放就调用 setSelectedZoomId，循环结束后
最后一个 auto-zoom 处于选中态。SettingsPanel 以 !hasTimelineSelection 作为
导出面板渲染条件，导致用户点完"自动添加缩放"后导出按钮消失，必须先点剪辑
轨道取消选中才能导出。

批量 suggest 路径移除选中副作用；单个手动添加 (handleZoomAdded) 保持自动
选中不变。

Closes #610

src/components/video-editor/VideoEditor.tsx

@@ -864,11 +864,10 @@ export default function VideoEditor() {
 				customScale: ZOOM_DEPTH_SCALES[DEFAULT_ZOOM_DEPTH],
 				focus: clampFocusToDepth(focus, DEFAULT_ZOOM_DEPTH),
 			};
+			// Bulk suggest must not steal selection — keeping a zoom selected hides
+			// the export panel (SettingsPanel gates it on !hasTimelineSelection),
+			// trapping users who just want to export after auto-zoom.
 			pushState((prev) => ({ zoomRegions: [...prev.zoomRegions, newRegion] }));
-			setSelectedZoomId(id);
-			setSelectedTrimId(null);
-			setSelectedAnnotationId(null);
-			setSelectedBlurId(null);
 		},
 		[pushState],
 	);