修复PSD模板画布自动适配时机问题

- 添加延迟执行确保DOM已渲染
- 添加尺寸有效性检查

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

components/agents/AgentPsdTemplateEditorDialog.tsx

@@ -472,18 +472,23 @@ export function AgentPsdTemplateEditorDialog({
     setTextAssignments(initialState.textAssignments);
     setSelectedLayerId(getPreferredSelectedLayerId(selectedTemplate));
 
-    // 自动适配缩放比例
-    if (selectedTemplate && previewViewportRef.current) {
-      const viewport = previewViewportRef.current;
-      const padding = 32; // 预留边距
-      const availableWidth = viewport.clientWidth - padding;
-      const availableHeight = viewport.clientHeight - padding;
+    // 自动适配缩放比例（延迟执行确保 DOM 已渲染）
+    if (selectedTemplate) {
+      setTimeout(() => {
+        if (previewViewportRef.current) {
+          const viewport = previewViewportRef.current;
+          const padding = 32;
+          const availableWidth = viewport.clientWidth - padding;
+          const availableHeight = viewport.clientHeight - padding;
 
-      const scaleX = availableWidth / selectedTemplate.width;
-      const scaleY = availableHeight / selectedTemplate.height;
-      const fitScale = Math.min(scaleX, scaleY, 1); // 不超过1倍
-
-      setStageScale(fitScale);
+          if (availableWidth > 0 && availableHeight > 0) {
+            const scaleX = availableWidth / selectedTemplate.width;
+            const scaleY = availableHeight / selectedTemplate.height;
+            const fitScale = Math.min(scaleX, scaleY, 1);
+            setStageScale(fitScale);
+          }
+        }
+      }, 100);
     }
   }, [open, selectedTemplate, sourceImageUrl]);