[client] cursor: restore Wayland edge synchronization

Keep guest-to-host pointer synchronization active while an attempted
surface exit is blocked by the edge of a Wayland output. Continue
forwarding relative motion and wait for wl_pointer.leave before marking
the cursor outside the window.

Distinguish whole-surface releases from exits into letterbox space so
the expected asynchronous release callback cannot disable the feedback
loop before the pointer is confined again.

Treat Wayland pointer capability loss as a real leave so an unrelated
inactive callback cannot be mistaken for the intentional release.

client/displayservers/Wayland/input.c

@@ -553,7 +553,10 @@ static void waylandCleanUpPointer(bool notify)
   MLOG(confSeq, "conf destroy id=%u why=pointer", confId);
 
   if (event)
+  {
+    app_handleEnterEvent(false);
     app_handleGrabEvent(false);
+  }
 }
 
 // Seat-handling listeners.