Show each screen's name on it so I can tell them apart in person

"Which screen is this?" — shows each targeted screen's own name in large text on its ticker bar for about 90 seconds ("Screen {number}" for a screen with no name), so a person standing in front of an unlabeled TV can read it out. Optional deviceIds targets specific screens; omitted or empty targets every online, non-broadcast screen. Each result includes showsWithinSeconds (up to 60s — the TV app's poll interval) and until (when it reverts). Try GET /v1/devices?near= first when the caller's location is known; identify is the fallback for telling several screens in one room apart.