feat: switch dynamic import on theme

Author: soranjiro

apps/web/src/lib/themes/index.ts

@@ -1,15 +1,14 @@
 import type { Theme } from '@tabitabi/types';
-import minimalTheme from './minimal';
-import standardTheme from './standard';
-
-const themes: Record<string, Theme> = {
-  minimal: minimalTheme,
-  standard: standardTheme
-};
 
+// 動的 import に切り替え（未選択テーマをバンドルしない）
 export async function loadTheme(themeId: string): Promise<Theme> {
-  const theme = themes[themeId] || themes.minimal;
-  return theme;
+  switch (themeId) {
+    case 'standard':
+      return (await import('./standard')).default;
+    case 'minimal':
+    default:
+      return (await import('./minimal')).default;
+  }
 }
 
 export function getEnabledFeatures(theme: Theme): string[] {
@@ -18,12 +17,14 @@ export function getEnabledFeatures(theme: Theme): string[] {
     .map(([name]) => name);
 }
 
+// メタ情報だけを静的に保持（テーマ本体は読み込まない）
+const THEME_CATALOG: Array<{ id: AvailableTheme; name: string; description: string }> = [
+  { id: 'minimal', name: 'ミニマル', description: '必要最小限のシンプルなテーマ' },
+  { id: 'standard', name: 'スタンダード', description: 'デフォルトテーマ' }
+];
+
 export function getAvailableThemes(): Array<{ id: string; name: string; description: string }> {
-  return Object.values(themes).map(theme => ({
-    id: theme.id,
-    name: theme.name,
-    description: theme.description
-  }));
+  return THEME_CATALOG;
 }
 
 export const availableThemes = ['minimal', 'standard'] as const;