* feat: add condition node functionality with CEL evaluation
- Introduced ConditionNode to support conditional branching in workflows.
- Implemented CEL evaluation for state updates and condition expressions.
- Updated WorkflowEngine to handle condition nodes and their execution logic.
- Enhanced validation for workflows to ensure condition nodes have at least two outgoing edges and valid expressions.
- Modified frontend components to support new condition node type and its configuration.
- Added necessary types and interfaces for condition cases and state operations.
- Updated requirements to include cel-python for expression evaluation.
* mini-fixes
* feat(workflow): improve UX
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Co-authored-by: Alex <a@tushynski.me>
