Add a hold-by-name gesture to ui-trace

A row held to select it was the one gesture that could only be written as a
pair of coordinates: `tap`'s press is 60ms so nothing sees a long press, and
`holddrag` takes numbers and always drags afterwards. `hold 'helper 3'`
resolves the label the way `tap` does -- the resolution is now `locate`,
shared by both -- and holds the press past the platform's 500ms threshold.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -175,6 +175,13 @@ measured, which reads exactly like a result rather than like a failure. Asked
 for by Iris on 2026-09-03, after ai-app's two benchmark scripts pressed a
 header button at `tap 723 205` and that button moved.
 
+`hold 'helper 3'` is the same resolution with a press held past the
+platform's 500ms long-press threshold, for a row that is held to select it or
+anything else that distinguishes the two. Neither other action reaches it:
+`tap`'s press is 60ms, and `holddrag` takes coordinates and always drags
+afterwards — so the one gesture "hold a list row" needs was the one that could
+only be written as a pair of numbers.
+
 A label that is not on screen ends the recording with `# error action failed`
 and a non-zero exit, so a run that could not press what it meant to press
 produces no numbers at all.