Function visual_move_up

src/text_input.rs:1677–1685

Navigate cursor one visual line up. Returns the new global cursor position. `col` is the desired column (preserved across up/down moves).

(visual_lines: &[VisualLine], cursor_pos: usize)

/// Navigate cursor one visual line up. Returns the new global cursor position.
/// `col` is the desired column (preserved across up/down moves).
pub fn visual_move_up(visual_lines: &[VisualLine], cursor_pos: usize) -> usize {
    let (line, col) = cursor_to_visual_pos(visual_lines, cursor_pos);
    if line == 0 {
        return 0; // Already on first visual line → move to start
    }
    let target_line = &visual_lines[line - 1];
    let new_col = col.min(target_line.char_count);
    target_line.global_char_start + new_col
}

/// Navigate cursor one visual line down. Returns the new global cursor position.
pub fn visual_move_down(visual_lines: &[VisualLine], cursor_pos: usize, text_len: usize) -> usize {