fix: correct inverted logic in prepare_paths - entities without paths were being skipped

The condition 'if ambulatory.current_path.is_none() || pending_async.is_some()' was backwards.
It should skip entities that ALREADY have a path, not entities WITHOUT a path.

Fixed to properly skip entities with existing paths or pending async tasks.

src/entities/shared_systems/pathfinding.rs

@@ -176,10 +176,18 @@ pub fn prepare_paths(
     tilemap: Res<TileMap>,
 ) {
     for (entity, mut ambulatory, transform, pending_async) in query.iter_mut() {
-        if let Some(target) = ambulatory.target {
-            if ambulatory.current_path.is_none() || pending_async.is_some() {
+        if ambulatory.current_path.is_some() {
             continue;
         }
+        if pending_async.is_some() {
+            continue;
+        }
+        if ambulatory.target.is_none() {
+            continue;
+        }
+        let Some(target) = ambulatory.target else {
+            continue;
+        };
         let start = transform.translation.as_ivec3();
         let goal = target.as_ivec3() - ivec3(0, 0, ITILE_SIZE);
         let distance = octile_distance_3d(start, goal) / ITILE_SIZE;
@@ -216,7 +224,6 @@ pub fn prepare_paths(
             }
         }
     }
-    }
 }
 
 pub fn splice_completed_async_paths(