openInput() sends an implicit ACTION_VIEW on the passthrough channel URI and
only tries the theme's input_action when nothing claims it. On an RCA Android
TV 9 (RTK2851P) the firmware has no Live TV app for that URI and ES File
Explorer declares a VIEW filter for the same MIME type, so HDMI 1 opened the
file manager. Records the mechanism, the query-activities check, why
live_tv_package (setPackage on the Live TV row only) cannot filter it, and the
source_panel_service workaround. Pins the note in themes/README's input_action
row.
