Fix wait_for_target_processed returning before status is stable.

Add a confirmation check after target transitions from PROCESSING to guard
against eventual consistency issues where other endpoints still see the
target as processing.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: adamtheturtle

src/vws/vws.py

@@ -343,7 +343,15 @@ def wait_for_target_processed(
         while True:
             report = self.get_target_summary_report(target_id=target_id)
             if report.status != TargetStatuses.PROCESSING:
-                return
+                # Wait and verify once more to guard against the target
+                # still being seen as processing by other endpoints due
+                # to eventual consistency.
+                time.sleep(seconds_between_requests)
+                report = self.get_target_summary_report(
+                    target_id=target_id,
+                )
+                if report.status != TargetStatuses.PROCESSING:
+                    return
 
             elapsed_time = time.monotonic() - start_time
             if elapsed_time > timeout_seconds:  # pragma: no cover