refactor(editor): optimize pasting process of attachments and images (#12276)

Related to: [BS-3146](https://linear.app/affine-design/issue/BS-3146/import-paste-接口改进优化)

blocksuite/framework/store/src/transformer/assets.ts

@@ -1,5 +1,6 @@
 import { BlockSuiteError, ErrorCode } from '@blocksuite/global/exceptions';
 
+import type { BlockProps } from '../model';
 import type { BlobCRUD } from './type';
 
 type AssetsManagerConfig = {
@@ -18,6 +19,16 @@ function makeNewNameWhenConflict(names: Set<string>, name: string) {
 }
 
 export class AssetsManager {
+  // `blockId` is the key.
+  readonly uploadingAssetsMap = new Map<
+    string,
+    {
+      blob: Blob;
+      abortController?: AbortController;
+      mapInto: (blobId: string) => Partial<BlockProps>;
+    }
+  >();
+
   private readonly _assetsMap = new Map<string, Blob>();
 
   private readonly _blob: BlobCRUD;

blocksuite/framework/store/src/transformer/transformer.ts

@@ -245,8 +245,9 @@ export class Transformer {
     parent?: string,
     index?: number
   ): Promise<Slice | undefined> => {
-    SliceSnapshotSchema.parse(snapshot);
     try {
+      SliceSnapshotSchema.parse(snapshot);
+
       this._slots.beforeImport.next({
         type: 'slice',
         snapshot,
@@ -525,11 +526,11 @@ export class Transformer {
     for (let index = 0; index < nodes.length; index++) {
       const node = nodes[index];
       const { draft } = node;
-      const { id, flavour } = draft;
+      const { id, flavour, props } = draft;
 
       const actualIndex =
         startIndex !== undefined ? startIndex + index : undefined;
-      doc.addBlock(flavour, { id, ...draft.props }, parentId, actualIndex);
+      doc.addBlock(flavour, { id, ...props }, parentId, actualIndex);
 
       const model = doc.getBlock(id)?.model;
       if (!model) {