[BUG] SequentialWorkflow drift detection can rerun indefinitely on persistent low scores

[shaun0927]

Describe the bug
SequentialWorkflow._run_drift_detection() reruns the pipeline in a while True loop until the drift score crosses the threshold. If the drift score stays low, the workflow keeps rerunning without any retry ceiling.

That can burn tokens indefinitely and prevents the workflow from terminating in a bounded way when the judge never improves.

To Reproduce

1. Create a SequentialWorkflow with drift_detection=True.
2. Mock the drift agent so it always returns a score below the threshold.
3. Mock agent_rearrange.run() to return any string.
4. Call run().

At HEAD the loop is:

while True:
    ...
    if score >= self.drift_threshold:
        break
    result = self.agent_rearrange.run(**run_kwargs)

with no retry budget or timeout.

Expected behavior
Drift-triggered reruns should stop after a bounded number of attempts (or an explicit time budget) and return the latest result or raise a controlled failure.

Additional context

• Confirmed locally against master (cc1667a1).
• Relevant code: swarms/structs/sequential_workflow.py:231-257.
• In a local source-derived repro with an always-low judge score, the workflow reran hundreds of times in well under a second before I interrupted it.
• Related feature issue/PR: [feat][SequentialWorkflow] Drift Detection Agent #1517 and [FEAT] add DriftDetectionAgent #1522. I did not find an existing issue for the missing rerun cap itself.