fix(canvas): 画布图片生成 - 参考图超限时停止生成并提示清理连线

保留全部已连接参考图，在首次生成、重试和任务入口统一校验模型上限。

web/src/pages/canvas/canvas-image-generation-executor.ts

@@ -3,7 +3,7 @@ import { nanoid } from "nanoid";
 import { NODE_DEFAULT_SIZE } from "@/constant/canvas";
 import { canGenerateImageInPlace, findAvailableGenerationGroupPosition, imageGenerationChildPosition, imageGenerationGroupSize } from "@/lib/canvas/canvas-generation-layout";
 import { nodeSizeFromRatio } from "@/lib/canvas/canvas-node-size";
-import { buildImageGenerationMetadata, getGenerationCount, isGenerationCanceled, limitCanvasImageReferences, runCanvasGenerationTaskToConsumer } from "@/lib/canvas/canvas-project-generation";
+import { canvasImageReferenceLimitError, buildImageGenerationMetadata, getGenerationCount, isGenerationCanceled, runCanvasGenerationTaskToConsumer } from "@/lib/canvas/canvas-project-generation";
 import { CONTENT_MODERATION_ERROR_CODE, generationFailureMetadata, type GenerationFailureMetadata } from "@/lib/generation-error";
 import { CanvasNodeType, type CanvasNodeData } from "@/types/canvas";
 
@@ -39,13 +39,18 @@ export async function executeImageGeneration({
     showError,
     registerPendingNodeIds,
 }: CanvasGenerationExecution) {
+    const referenceLimitError = canvasImageReferenceLimitError(generationConfig, generationContext.referenceImages);
+    if (referenceLimitError) {
+        showError(referenceLimitError);
+        return;
+    }
     const count = getGenerationCount(generationConfig.count);
     const isConfigNode = sourceNode?.type === CanvasNodeType.Config;
     const isImageNode = sourceNode?.type === CanvasNodeType.Image;
     const reuseSourceNode = canGenerateImageInPlace(sourceNode);
     const directCopiedBatch = count > 1 && isImageNode && Boolean(sourceNode?.metadata?.content) && (Boolean(sourceNode?.metadata?.copiedFromNodeId) || sourceNode?.title.endsWith(" Copy"));
     // 已有图片生成新结果并保留旧版本；参考图只来自入边，避免把旧结果误当成自身输入。
-    const referenceImages = limitCanvasImageReferences(generationConfig, generationContext.referenceImages);
+    const referenceImages = generationContext.referenceImages;
     const generationType = referenceImages.length ? ("edit" as const) : ("generation" as const);
     const generationMetadata = buildImageGenerationMetadata(generationType, generationConfig, count, referenceImages);
     const parentConfig = NODE_DEFAULT_SIZE[isConfigNode ? CanvasNodeType.Config : isImageNode ? CanvasNodeType.Image : CanvasNodeType.Text];