refactor: remove digest fields from db and item struct

src/modes/save.rs

@@ -52,8 +52,6 @@ pub fn mode_save(
         ts: Utc::now(),
         size: None,
         compression: compression_type.to_string(),
-        digest_type: digest_type.to_string(),
-        digest_value: Some(String::new()),
     };
 
     let id = db::insert_item(conn, item.clone())?;