refactor(frontend): use* 関数の格納場所のフォルダ名を composables に変更 (#16004)

* refactor(frontend): use* 関数の格納場所を正式名称（composables）に変更

* migrate

* move useLoading

packages/frontend/src/composables/use-leave-guard.ts

@@ -0,0 +1,50 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type { Ref } from 'vue';
+
+export function useLeaveGuard(enabled: Ref<boolean>) {
+	/* TODO
+	const setLeaveGuard = inject('setLeaveGuard');
+
+	if (setLeaveGuard) {
+		setLeaveGuard(async () => {
+			if (!enabled.value) return false;
+
+			const { canceled } = await os.confirm({
+				type: 'warning',
+				text: i18n.ts.leaveConfirm,
+			});
+
+			return canceled;
+		});
+	} else {
+		onBeforeRouteLeave(async (to, from) => {
+			if (!enabled.value) return true;
+
+			const { canceled } = await os.confirm({
+				type: 'warning',
+				text: i18n.ts.leaveConfirm,
+			});
+
+			return !canceled;
+		});
+	}
+	*/
+
+	/*
+	function onBeforeLeave(ev: BeforeUnloadEvent) {
+		if (enabled.value) {
+			ev.preventDefault();
+			ev.returnValue = '';
+		}
+	}
+
+	window.addEventListener('beforeunload', onBeforeLeave);
+	onUnmounted(() => {
+		window.removeEventListener('beforeunload', onBeforeLeave);
+	});
+	*/
+}