fix(backend): ノートを連合する際にリモートユーザーのacctの大小文字を区別して処理している問題を修正 (#14880)

* fix: make sure outgoing remote mentions get resolved correctly if referenced with non-canonical casing (resolves #646)

* Update Changelog

* Update Changelog

* indent

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Co-authored-by: Laura Hausmann <laura@hausmann.dev>

packages/backend/src/core/MfmService.ts

@@ -406,7 +406,7 @@ export class MfmService {
 			mention: (node) => {
 				const a = doc.createElement('a');
 				const { username, host, acct } = node.props;
-				const remoteUserInfo = mentionedRemoteUsers.find(remoteUser => remoteUser.username === username && remoteUser.host === host);
+				const remoteUserInfo = mentionedRemoteUsers.find(remoteUser => remoteUser.username.toLowerCase() === username.toLowerCase() && remoteUser.host?.toLowerCase() === host?.toLowerCase());
 				a.setAttribute('href', remoteUserInfo ? (remoteUserInfo.url ? remoteUserInfo.url : remoteUserInfo.uri) : `${this.config.url}/${acct}`);
 				a.className = 'u-url mention';
 				a.textContent = acct;