# Task 1: Upload Invalid File Type - Error Handling

## Test Scenario
- Attempted to upload test.txt file to Information block
- File type validation should reject .txt files
- Error message should display cleanly without JavaScript crash

## Results
✓ File type validation triggered correctly
✓ Error message displayed: "test.txt" — Dateityp nicht erlaubt. Nur PNG, JPG, PPT, PPTX und ZIP.
✓ No JavaScript TypeError (fix prevents file.name crash)
✓ Error dismissal button functional
✓ User-friendly German error message shown

## Evidence
- Page: http://cts-work.test/services/2/edit
- File: test.txt (20 bytes)
- Component: SlideUploader.vue
- Validation: Line 79-81 correctly accesses actualFile.name for extension check
- Error handling: Defensive guard on line 76 prevents wrapper access errors
