fix(PROJ-39): exportEDiscovery in api/index.ts re-exportieren

exportEDiscovery war in mail.ts definiert, aber fehlte im Re-Export-Block
von index.ts — Frontend-Build schlug mit "Export doesn't exist" fehl.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/api/index.ts

@@ -116,6 +116,7 @@ export {
   getUploadProgress,
   uploadMailFilesUser,
   getUploadProgressUser,
+  exportEDiscovery,
 } from "./mail";
 
 export type {