Fix: Task failure handling when task is not a Signature

[yedidyakfir]

Summary

When a task fails but it is not a Signature type, the failure is not handled correctly. This is a critical bug that needs immediate attention.

Problem

The current implementation assumes tasks are Signatures when handling failures. When a non-Signature task fails, the error handling path doesn't work as expected.

Expected Behavior

Task failures should be handled correctly regardless of whether the task is a Signature or another task type (e.g., Swarm, Chain).

Tasks

• Investigate the failure handling code path for non-Signature tasks
• Implement proper error handling for all task types
• Add unit tests to verify failure handling for non-Signature tasks
• Add integration tests to ensure end-to-end behavior is correct

[github-actions]

Closed by #56.