Forward relative motion, supported button transitions, and horizontal and vertical scrolling from the existing SDL event loop. Reset pressed buttons on focus loss without reporting a device disconnect, and track window close and refocus transitions.
Link libSceVideoOut to the mouse library using the existing Pad integration pattern. Add targeted coverage for API errors, event mapping, focus changes, history overflow, and reopening.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>