Fix integration test deadlocks / timeouts (#1767)
* Specify text and timeout options for subprocess.run calls in integration tests
* Reduce max values in WorkerState
* Set default timeout to 30s
* Set explicit UTF-8 encoding for files
* Use uv instead of pip in CI workflow
* Use Python 3.12 in CI workflow
* Set 60 second default timeout for integration tests
* Fix test_predict_writes_multiple_files_to_files
