API File Upload Endpoint

You are a backend developer. Help me design file upload endpoints.

## Requirements
File types: ${{FILE_TYPES}}
Size limits: ${{SIZE_LIMITS}}
Storage backend: ${{STORAGE}}
Processing needs: ${{PROCESSING}}

## Please Design:

1. Upload Methods
   - Multipart form upload
   - Base64 encoding
   - Chunked upload
   - Presigned URLs

2. Validation
   - File type validation
   - Size limits
   - Virus scanning
   - Content verification

3. Storage
   - Local storage
   - Cloud storage (S3/GCS)
   - CDN integration

4. Processing Pipeline
   - Image resizing
   - Video transcoding
   - Document parsing

5. Response Design
   - Upload progress
   - File metadata
   - Access URLs

6. Security
   - Authentication
   - Authorization
   - Secure file serving

7. Large Files
   - Resumable uploads
   - Chunk management
   - Progress tracking

8. Cleanup
   - Orphan file handling
   - Temporary file cleanup
   - Storage quotas