* [BREAKING] refactor: Normalize WorkflowBuilder APIs
* "partitioner" => "assigner"
* normalize ordering so sources always to the left of targets for edges
* normalize parameter ordering so sources and targets are always first arguments
* remove `params` (users should use collection expressions instead)
* refactor: Align name with Python
* Add workflow as an agent with observability sample
* Address comment
* Fix formatting
* enable sensitive data
* enable sensitive data for sub agents
* adjust aggregator handlers