refactor(editor): cleanup dead code (#12281)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **Refactor**
  - Streamlined and consolidated block and inline extension exports by removing multiple block-spec and inline extension arrays from public APIs.
  - Reduced exported constants, types, and utility functions related to various block and embed features.
  - Simplified the codebase by removing deprecated type guards, adapter extensions, and redundant extension groupings.
- **Chores**
  - Cleaned up internal APIs by deleting unused exports, imports, and outdated code, enhancing maintainability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/attachment/src/attachment-spec.ts

@@ -1,33 +0,0 @@
-import { AttachmentBlockSchema } from '@blocksuite/affine-model';
-import { SlashMenuConfigExtension } from '@blocksuite/affine-widget-slash-menu';
-import { BlockViewExtension, FlavourExtension } from '@blocksuite/std';
-import type { ExtensionType } from '@blocksuite/store';
-import { literal } from 'lit/static-html.js';
-
-import { AttachmentBlockAdapterExtensions } from './adapters/extension.js';
-import { AttachmentBlockInteraction } from './attachment-edgeless-block.js';
-import { AttachmentDropOption } from './attachment-service.js';
-import { attachmentSlashMenuConfig } from './configs/slash-menu.js';
-import { createBuiltinToolbarConfigExtension } from './configs/toolbar';
-import {
-  AttachmentEmbedConfigExtension,
-  AttachmentEmbedService,
-} from './embed';
-
-const flavour = AttachmentBlockSchema.model.flavour;
-
-export const AttachmentBlockSpec: ExtensionType[] = [
-  FlavourExtension(flavour),
-  BlockViewExtension(flavour, model => {
-    return model.parent?.flavour === 'affine:surface'
-      ? literal`affine-edgeless-attachment`
-      : literal`affine-attachment`;
-  }),
-  AttachmentDropOption,
-  AttachmentEmbedConfigExtension(),
-  AttachmentEmbedService,
-  AttachmentBlockAdapterExtensions,
-  AttachmentBlockInteraction,
-  createBuiltinToolbarConfigExtension(flavour),
-  SlashMenuConfigExtension(flavour, attachmentSlashMenuConfig),
-].flat();

blocksuite/affine/blocks/attachment/src/index.ts

@@ -1,7 +1,6 @@
 export * from './adapters';
 export * from './attachment-block';
 export * from './attachment-service';
-export * from './attachment-spec';
 export { attachmentViewDropdownMenu } from './configs/toolbar';
 export * from './edgeless-clipboard-config';
 export {