feat(theme): sync defaultTheme=ClassicLight enabledThemes=[ClassicLight,ModernLight] across all 6 fallback locations

app/composables/useSiteConfig.js

@@ -60,8 +60,8 @@ export const useSiteConfig = () => {
         enableReplayRequests: false,
         enableCollaborativeSubmission: true,
         enableSubmissionRemarks: false,
-        defaultTheme: 'System',
-        enabledThemes: '["System","ClassicDark","ClassicLight","ModernLight"]'
+        defaultTheme: 'ClassicLight',
+        enabledThemes: '["ClassicLight","ModernLight"]'
       }
       isLoaded.value = true
     } finally {

app/drizzle/schema.ts

@@ -350,8 +350,8 @@ export const systemSettings = pgTable('SystemSettings', {
   autoBackupConfig: text('autoBackupConfig'),
   statisticsCode: text('statisticsCode'),
   statisticsCodeEnabled: boolean('statisticsCodeEnabled').default(false).notNull(),
-  defaultTheme: text('defaultTheme').default('System').notNull(),
-  enabledThemes: text('enabledThemes').default('[\"System\",\"ClassicDark\",\"ClassicLight\",\"ModernLight\"]').notNull(),
+  defaultTheme: text('defaultTheme').default('ClassicLight').notNull(),
+  enabledThemes: text('enabledThemes').default('[\"ClassicLight\",\"ModernLight\"]').notNull(),
   enabledPlatforms: text('enabledPlatforms'),
   platformOrder: text('platformOrder'),
 });