feat(canvas): 画布媒体工作流 - 支持批量连线、失败重试与模型能力增强

合并 PR #230。保留当前主线样式与组件结构，吸收批量连线、失败批次重试、媒体模型能力和相关后端增强，并修复集成检查发现的分辨率选择器启用条件与测试稳定性问题。

web/src/types/canvas.ts

@@ -176,6 +176,7 @@ export type CanvasNodeMetadata = {
     isBatchRoot?: boolean;
     batchRootId?: string;
     batchChildIds?: string[];
+    batchFailedCount?: number;
     batchUsesReferenceImages?: boolean;
     primaryImageId?: string;
     imageBatchExpanded?: boolean;
@@ -316,6 +317,7 @@ export type CanvasNodeMetadata = {
         sourceHeight?: number;
         providerSize?: string;
         maskStorageKey?: string;
+        editMode?: "provider-mask" | "local-composite";
     };
     portraitTexture?: PortraitTextureSettings;
 };