Bare `pixelpass` now opens a dialoguer-driven Host/View menu instead of
going straight to host mode. Host path copies the ticket to the system
clipboard via arboard with silent print-only fallback. View path
prompts for the ticket, then after the local listener binds prompts
mpv-vs-VLC and spawns it detached (setsid + null stdio) so the player
survives pixelpass exiting.
Headless invocations (`pixelpass <ticket>`, `pixelpass --repair`)
unchanged. Per spec at ~/Documents/pixelpass-interactive-mode-spec.md.