docs: replace ASCII screenshot with actual image

Author: NDXDeveloper

README.md

@@ -74,21 +74,7 @@ slashsum myfile.iso --save
 
 ## 📸 Screenshot
 
-```
-$ slashsum ubuntu-22.04.3-desktop-amd64.iso
-
-slashsum v0.2.1 - 774ce26
-File: ubuntu-22.04.3-desktop-amd64.iso
-Size:    4.68 GB (5033165312 bytes)
-CRC32:   8d7be4e9
-MD5:   a3b9d148c5f8d237f735a5d9795a2345
-SHA1:  2aae6c35c94fcfb415dbe95f408b9ce91ee846ed
-SHA256: b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9
-SHA512: 309ecc489c12d6eb4cc40f50c902f2b4d0ed77ee511a7c7a9bcd3ca86d4cd86f989dd35bc5ff499670da34255b45b0cfd830e81f605dcf7dc5542e93ae9cd76f
-Time:  12.45s
-```
-
-> 💡 **Tip**: Add a real screenshot or GIF in `store-assets/screenshots/` and update this section with `![Screenshot](store-assets/screenshots/slashsum-terminal.png)`
+![Slashsum terminal output](store-assets/screenshots/slashsum-terminal.png)
 
 ---