RiftLift 0.9.0 alpha 6

Alpha 6 makes launch troubleshooting easier from the GUI and addresses the reported interrupted-launch diagnostics. Users can now enable persistent Debug logging from the top bar; RiftLift saves detailed Proton output in bounded diagnostic storage and tells doctor whether the failing launch was captured with debug logging. Doctor now focuses on genuinely recent launches, labels missing outcomes as interrupted, filters known XRizer utility-probe noise, and gives clearer next steps. The GUI also refuses to close while an operation is active, cancelled launches record a useful error name, and OpenVR application identification is limited to the OpenVR backend. README screenshots have been refreshed for the current interface.