Add @workflow.init decorator to python.md Key Concepts (#57)

* docs: add @workflow.init decorator to python.md Key Concepts

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* Apply suggestion from @brianstrauch

* Update references/python/python.md

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Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: 2 people

references/python/python.md

@@ -98,6 +98,7 @@ if __name__ == "__main__":
 
 ### Workflow Definition
 - Use `@workflow.defn` decorator on class
+- Put any state initialization logic in the `__init__` of your workflow class to guarantee that it happens before signals/updates arrive. If your state initialization logic requires the workflow parameters, then add the `@workflow.init` decorator and parameters to your `__init__`.
 - Use `@workflow.run` on the entry point method
 - Must be async (`async def`)
 - Use `@workflow.signal`, `@workflow.query`, `@workflow.update` for handlers