fix: remove stray space in upload filename format string

src/api/upload.rs

@@ -189,4 +189,16 @@ pub async fn upload_image(
     })))
 }
 
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn filename_format_no_spaces() {
+        let now_str = "120000";
+        let uuid = "abc-123";
+        let ext = "jpg";
+        let file_name = format!("{}.{}.{}", now_str, uuid, ext);
+        assert!(!file_name.contains(' '), "filename should not contain spaces: got '{}'", file_name);
+    }
+}
+