refactor(frontend): カスタムディレクティブの型付け (#16659)

* refactor(frontend): カスタムディレクティブの型付け

* fix

packages/frontend/src/directives/panel.ts

@@ -6,8 +6,8 @@
 import type { Directive } from 'vue';
 import { getBgColor } from '@/utility/get-bg-color.js';
 
-export default {
-	mounted(src, binding, vn) {
+export const panelDirective = {
+	mounted(src) {
 		const parentBg = getBgColor(src.parentElement) ?? 'transparent';
 
 		const myBg = getComputedStyle(window.document.documentElement).getPropertyValue('--MI_THEME-panel');
@@ -18,4 +18,4 @@ export default {
 			src.style.backgroundColor = 'var(--MI_THEME-panel)';
 		}
 	},
-} as Directive;
+} as Directive<HTMLElement>;