chore: 著作権とライセンスについての情報を各ファイルに追加する (#11348)

* chore: Add the SPDX information to each file

Add copyright and licensing information as defined in version 3.0 of
the REUSE Specification.

* tweak format

---------

Co-authored-by: syuilo <Syuilotan@yahoo.co.jp>

packages/frontend/src/components/MkPostFormAttaches.vue

@@ -1,3 +1,8 @@
+<!--
+SPDX-FileCopyrightText: syuilo and other misskey contributors
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
 <template>
 <div v-show="props.modelValue.length != 0" :class="$style.root">
 	<Sortable :modelValue="props.modelValue" :class="$style.files" itemKey="id" :animation="150" :delay="100" :delayOnTouchOnly="true" @update:modelValue="v => emit('update:modelValue', v)">