enhance(frontend): Playの説明欄にMFMを使えるように (#12899)

* (enhance) Playの説明欄にMFMを使えるように

* Update Changelog

* use class for mfm component

* Update packages/frontend/src/pages/flash/flash-edit.vue

Co-authored-by: 1Step621 <86859447+1STEP621@users.noreply.github.com>

* Update flash.vue

* Update CHANGELOG.md

---------

Co-authored-by: 1Step621 <86859447+1STEP621@users.noreply.github.com>

packages/frontend/src/pages/flash/flash.vue

@@ -25,7 +25,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 					<div v-else :class="$style.ready">
 						<div class="_panel main">
 							<div class="title">{{ flash.title }}</div>
-							<div class="summary">{{ flash.summary }}</div>
+							<div class="summary"><Mfm :text="flash.summary"/></div>
 							<MkButton class="start" gradate rounded large @click="start">Play</MkButton>
 							<div class="info">
 								<span v-tooltip="i18n.ts.numberOfLikes"><i class="ti ti-heart"></i> {{ flash.likedCount }}</span>