test(headers): add comprehensive tests for download response headers

- Test Content-Disposition inline/attachment behavior
- Test query param overrides (?download, ?inline)
- Test RFC 5987 filename encoding with special characters
- Test Content-Type for files, folders, encrypted content
- Test Content-Encoding and decompression flags
- Test Accept-Ranges for various scenarios
- Test range request handling

Author: 0xjeremyfrank