fix(try): remove the call to a child workflow - #550

Codex PR Review

• High: pkg/zigflow/tasks/task_builder_try.go#L57-L70 replaces child-workflow commands with inline execution without Temporal versioning. Replaying any in-flight workflow whose history contains the former child-workflow command will become non-deterministic after deployment. Preserve the old implementation behind workflow.GetVersion, including child workflow registration, or introduce a new workflow type/version.

• Medium: pkg/zigflow/tasks/task_builder_try.go#L215-L220 executes the try body against the parent state directly. Successful tasks before a later failure can now mutate $data, $context, and $output visible to the catch and subsequent parent tasks. Child-workflow serialisation previously isolated those mutations. Clone the parent state before executing tryFn, and construct the catch state from the original parent state. Add a regression test with a mutating task followed by a failing task.

🚀 Preview deployed
🔗 https://zigflow.dev/preview/sje-remove-child-workflows

please let me know when the fix is ready and I can start testing it, thanks for addressing this!