Provisional paths were not being recorded to benchmark stats, causing
total_paths=0 while failed_paths accumulated. Now records:
- path_calc_times_us (timing)
- path_lengths (path length)
- nodes_expanded (A* nodes visited)
- failed_paths (when start/goal not standable)
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.
- Restored original target selection logic that validates is_standable_tile
- Fixed target position z-level checking (check floor tile then standable)
- Re-added check for completed paths (path_index >= path.len)
- This was the cause of 50,297 failed paths - entities targeting invalid positions
popertots