Connect to atomic rejection flow

Introduce atomic rejection for bulk submissions, remove dead moderation code, and clean exports:
- Replace direct DB updates in rejectSubmissionItems with atomic process-selective-rejection edge function call
- Add edge function invocation helper import
- Remove obsolete moderation actions (approvePhotoSubmission, rejectSubmissionItems, performModerationAction) and prune exports
- Update moderation index exports accordingly
- Ensure cascade handling uses atomic pipeline and avoid updateSubmissionStatusAfterRejection calls

src/lib/moderation/index.ts

@@ -28,16 +28,12 @@ export type { ResolvedEntityNames } from './entities';
 
 // Moderation actions
 export {
-  approvePhotoSubmission,
   approveSubmissionItems,
-  rejectSubmissionItems,
-  performModerationAction,
   deleteSubmission,
 } from './actions';
 
 export type {
   ModerationActionResult,
-  ModerationConfig,
   DeleteSubmissionConfig,
 } from './actions';