Function touch_ui_active 

pub fn touch_ui_active() -> bool

The signal the UI sizing policy consults to decide whether interactive targets must meet the touch minimum (see crate::widgets::menu::effective_metrics).

True when EITHER:

• the platform declared a mobile-touch profile (is_mobile_touch) — the app called set_input_profile with a mobile variant, so we know up front the user is on a phone/tablet; OR
• a real touch event has fired this session (crate::touch_state::touch_seen_this_session) — a runtime fallback for shells that forgot to call set_input_profile / crate::ux_scale::set_ux_scale (which has happened in real apps). Without it, such a phone would ship desktop-sized (26 CSS-px) menus; with it, the first touch flips the latch and the menus can never stay accidentally tiny.

Deliberately distinct from is_mobile_touch: that one drives the on-screen keyboard and other “no physical keyboard” features, which must NOT turn on just because a touchscreen laptop was tapped once. Sizing minimums are safe to raise on any touch input, so this signal is broader.