fix circular module dep: thread trackID counter via pointer instead of include

G4tracking cannot include G4EventManager.hh because G4event already
depends on G4tracking, creating a circular dependency. Fix: pass a
raw G4int* pointer to the event-level trackIDCounter from G4EventManager
through G4TrackingManager::SetTrackIDCounter into G4SteppingManager,
where ProcessSecondariesFromParticleChange uses it to pre-assign track
IDs without any new include.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

source/event/include/G4EventManager.hh

@@ -59,9 +59,6 @@ class G4EventManager
     static G4EventManager* GetEventManager();
       // This method returns the singleton pointer of G4EventManager.
 
-    G4int ReserveNextTrackID();
-      // Pre-assign the next sequential track ID to a secondary being born inside
-      // G4SteppingManager, so that its ID is available in UserSteppingAction.
 
     G4EventManager();
    ~G4EventManager();