Method update_text_input_pointer_scroll

src/engine.rs:6370–6753

Handle pointer-based scrolling for text inputs: scroll wheel and drag-to-scroll. Mobile-first: dragging scrolls the content rather than selecting text. `scroll_delta` contains (x, y) scroll wheel deltas. For single-line, both axes map to horizontal scroll. For multiline, y scrolls vertically.

(&mut self, scroll_delta: Vector2, touch_input_active: bool)

    /// `scroll_delta` contains (x, y) scroll wheel deltas. For single-line, both axes
    /// map to horizontal scroll. For multiline, y scrolls vertically.
    pub fn update_text_input_pointer_scroll(&mut self, scroll_delta: Vector2, touch_input_active: bool) -> bool {
        for idle in self.text_input_scrollbar_idle_frames.values_mut() {
            *idle = idle.saturating_add(1);
        }

        let mut consumed_scroll = false;

        let focused = self.focused_element_id;

        // --- Scroll wheel: scroll any hovered text input (even if unfocused) ---
        let has_scroll = scroll_delta.x.abs() > 0.01 || scroll_delta.y.abs() > 0.01;
        if has_scroll {
            let p = self.pointer_info.position;
            // Find the text input under the pointer
            let hovered_ti = self.text_input_element_ids.iter().enumerate().find(|&(_, &id)| {
                self.layout_element_map.get(&id)
                    .map(|item| {
                        let bb = item.bounding_box;
                        p.x >= bb.x && p.x <= bb.x + bb.width
                            && p.y >= bb.y && p.y <= bb.y + bb.height
                    })
                    .unwrap_or(false)
            });
            if let Some((idx, &elem_id)) = hovered_ti {
                let is_multiline = self.text_input_configs.get(idx)
                    .map(|cfg| cfg.is_multiline)
                    .unwrap_or(false);
                if let Some(state) = self.text_edit_states.get_mut(&elem_id) {
                    if is_multiline {
                        if scroll_delta.y.abs() > 0.01 {
                            state.scroll_offset_y -= scroll_delta.y;
                            if state.scroll_offset_y < 0.0 {
                                state.scroll_offset_y = 0.0;
                            }
                        }
                    } else {
                        let h_delta = if scroll_delta.x.abs() > scroll_delta.y.abs() {
                            scroll_delta.x
                        } else {
                            scroll_delta.y
                        };
                        if h_delta.abs() > 0.01 {
                            state.scroll_offset -= h_delta;
                            if state.scroll_offset < 0.0 {
                                state.scroll_offset = 0.0;
                            }
                        }
                    }
                    consumed_scroll = true;
                    self.text_input_scrollbar_idle_frames.insert(elem_id, 0);
                }
            }
        }

        // --- Drag scrolling (focused text input only) ---
        if focused == 0 {
            if self.text_input_drag_active {
                let pointer_state = self.pointer_info.state;