revert: completely remove all Sora functionality

frontend/src/components/admin/channel/types.ts

@@ -184,7 +184,6 @@ export function getPlatformTagClass(platform: string): string {
     case 'openai': return 'bg-emerald-100 text-emerald-700 dark:bg-emerald-900/30 dark:text-emerald-400'
     case 'gemini': return 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-400'
     case 'antigravity': return 'bg-purple-100 text-purple-700 dark:bg-purple-900/30 dark:text-purple-400'
-    case 'sora': return 'bg-rose-100 text-rose-700 dark:bg-rose-900/30 dark:text-rose-400'
     default: return 'bg-gray-100 text-gray-700 dark:bg-gray-900/30 dark:text-gray-400'
   }
 }