The quiet sibling of `tour`, in the same `desktop_ui` toolset and reading the
same `tour(action='targets')` discovery call: one bubble with an arrow, for a
sentence that would be clearer with a finger on the thing it's about. Dimming
the whole app to say "the model name is a button" is the wrong weight.
Fire-and-forget rather than a round-trip, because a tip is not a question and
blocking the turn on one would stall the reply it belongs to. The renderer
enforces the user's opt-out itself, so a stale config read can never put a
bubble on a screen that asked for none.