SwiftPythonRuntime v0.5.18

SwiftPython Commercial Runtime 0.5.18

• Prevents resource-pressure shedding from recycling a worker while a swift_bridge.call_async Future is still awaiting the worker’s explicit result acknowledgement.
• Ships hardened callback, stream, lifecycle, and respawn regression coverage, plus executable examples that exit nonzero when any selected example fails.
• Matched signed SwiftPythonRuntime XCFramework and SwiftPythonWorker; wire protocol remains version 5.

Source commit: mikhutchinson/SwiftPython@c040463

SwiftPM checksum: 929feb53d2c1cb3a73f5a6b706b8aba7a9d5c442488e66f5d61e54d1d5ef0cb3