* feat: Implement Checkpointing API
* refactor: Normalzie Namespaces and break out multi-class files
* feat: Support checkpointing in AIAgentHostExecutor
* test: Representation tests
* feat: Add Step-level Tracing and WorkflowEvents
* feat: Add Checkpointing Sample and Smoke Test
* Fixes an issue where StateManager was not properly clearing the incoming queued updates.
* Fixes order of checkpointing and in-step event publication
* Adds import of RunContext state on LoadCheckpoint
* Add re-firing of events for unserviced ExternalRequests on Checkpoint load
* docs: Add documentation to publics
* Also adds documentation to ICheckpointManager which may go public
* refactor: Fix Union Aggregators and add Tests
* fix: Fix issues raised in PR comments and remove dead code
Jacob Alber