Fix StateGraph losing loop iteration results when HIL interrupt occurs

Problem

When a Human-in-the-Loop interrupt occurred during a ForEach loop in the StateGraph orchestrator, the results from previous loop iterations were being lost.

Root Cause

The checkpoint mechanism was not properly preserving accumulated loop results when saving state during an interrupt.

Solution

Updated the StateGraph orchestrator to preserve all loop iteration results when a HIL interrupt occurs, ensuring they are available when execution resumes.

Impact

• Loop workflows with HIL interrupts now work correctly
• Data integrity maintained across interrupt boundaries
• Complex workflows with both loops and human interaction are now supported