fix: trace debug — show Stranger_NNN for unnamed traces instead of unknown

src/api/media_api.rs

@@ -345,6 +345,8 @@ async fn trace_video(
         trace_frames.entry(*tid).or_default().push(*fn_);
         if let Some(name) = name_opt {
             trace_identity.entry(*tid).or_insert_with(|| name.clone());
+        } else {
+            trace_identity.entry(*tid).or_insert_with(|| format!("Stranger_{:03}", tid));
         }
     }