chore: proxy image preview in frontend (#11957)

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

- **New Features**
	- Images and icons in bookmark cards are now loaded through an image proxy for improved reliability and consistency.
	- Embed blocks for GitHub, Loom, and YouTube now display banner and creator images via an image proxy service for enhanced image loading.

- **Refactor**
	- Simplified backend URL handling and proxy logic for images, resulting in more efficient processing and reduced complexity.
	- Consolidated image proxy middleware and services into a shared adapter module for streamlined imports and improved maintainability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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

@@ -6,7 +6,6 @@ import { literal } from 'lit/static-html.js';
 
 import { imageSlashMenuConfig } from './configs/slash-menu';
 import { createBuiltinToolbarConfigExtension } from './configs/toolbar';
-import { ImageProxyService } from './image-proxy-service';
 import { ImageDropOption } from './image-service';
 
 const flavour = ImageBlockSchema.model.flavour;
@@ -26,5 +25,3 @@ export const ImageBlockSpec: ExtensionType[] = [
   createBuiltinToolbarConfigExtension(flavour),
   SlashMenuConfigExtension(flavour, imageSlashMenuConfig),
 ].flat();
-
-export const ImageStoreSpec: ExtensionType[] = [ImageProxyService];