* [web] extract PythonExecutionContext and PythonRunner to manage pyodide execution per file
* [web] define worker URL in python execution context in order to avoid breaking cjs-based tests
* [web] use null check for doc contents to allow running empty python files
* [web] flush buffered editor ops before refreshing snapshot for python execution
* [web] catch getExecutionContext errors in python runner to prevent unhandled rejections
* [web] add PythonRunner unit tests and extract shared WorkerMock
* refactor: rename snapshot to state in PythonRunner
* fix: remove unnecessary path normalization in PythonExecutionProvider
* fix cypress tests
GitOrigin-RevId: 9c55586d982fe8df5b90374227005c6b83e94d1f
