perf(embed): improve embed performance (#14613)

* wip

* wip

* wip

* refactor

* refactor

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Co-authored-by: かっこかり <67428053+kakkokari-gtyih@users.noreply.github.com>

packages/frontend-embed/src/di.ts

@@ -7,9 +7,11 @@ import type { InjectionKey } from 'vue';
 import * as Misskey from 'misskey-js';
 import { MediaProxy } from '@@/js/media-proxy.js';
 import type { ParsedEmbedParams } from '@@/js/embed-page.js';
+import type { ServerContext } from '@/server-context.js';
 
 export const DI = {
 	serverMetadata: Symbol() as InjectionKey<Misskey.entities.MetaDetailed>,
 	embedParams: Symbol() as InjectionKey<ParsedEmbedParams>,
+	serverContext: Symbol() as InjectionKey<ServerContext>,
 	mediaProxy: Symbol() as InjectionKey<MediaProxy>,
 };