## Updated Moderation Workflow with django-pghistory

### Submission Lifecycle
1. **Change Proposal**  
   - Creates `pending` pghistory event with metadata:  
     ```python
     pghistory.track(
         pghistory.Snapshot('submission.pending'),
         status='pending'
     )
     ```
2. **Approval Process**  
   - Merges event into main history:  
     ```python
     event.pgh_label = 'approved_change'
     event.pgh_context['approver'] = request.user
     ```
3. **Rejection Handling**  
   - Preserves event with rejection context:  
     ```python
     event.pgh_label = 'rejected_change'
     event.pgh_context['reason'] = rejection_reason
     ```

### Moderation Admin Integration
```python
# moderation/admin.py
@admin.register(pghistory.models.Event)
class HistoryAdmin(admin.ModelAdmin):
    list_display = ('pgh_label', 'pgh_created_at', 'content_object')
    readonly_fields = ('pgh_data', 'pgh_context')