Drop the legacy "(none)" target fallback that quietly picked the first
attached device. Every device-bound subcommand now requires a `watch` or
`emulator` prefix (or DOCTATE_TARGET env var).
The emulator path never auto-picks a running emulator: even with exactly
one running, the menu shows so the user can boot a different AVD
instead. ADB_SERIAL / WEAR_AVD still bypass the menu for scripted runs.
Menu results now travel through a global RESOLVED_SERIAL/PICKED instead
of stdout+$(), so `die` inside the resolvers aborts the main shell
directly rather than getting swallowed by a command-substitution subshell.
Brummel
46880e1b06