function fig_geo_q4_mincover()
%FIG_GEO_Q4_MINCOVER  问题四：31 点最小命中集与前向半盘覆盖语义。

    S = fig_style();
    D = load_data(S, 'geo_q4');
    H = geom_helpers();
    fig = figure('Color', 'w', 'Visible', 'off');
    t = tiledlayout(fig, 1, 2, 'TileSpacing', 'compact', 'Padding', 'compact');

    % 左：Ω 内的 31 个覆盖点
    ax1 = nexttile(t);
    hold(ax1, 'on');
    hw = H.circle(ax1, [0 0], D.omega_r, pick_color(S, 'primary'), 1.2, '-');
    hp = plot(ax1, D.points(:, 1), D.points(:, 2), 'o', 'MarkerSize', 5, ...
              'MarkerFaceColor', pick_color(S, 'accent'), 'MarkerEdgeColor', 'none');
    hold(ax1, 'off');
    axis(ax1, 'equal');
    xlim(ax1, [-D.half, D.half]);
    ylim(ax1, [-D.half, D.half]);
    xlabel(ax1, 'x / m');
    ylabel(ax1, 'y / m');
    legend(ax1, [hw, hp], D.legend, 'Location', 'southoutside', ...
           'Orientation', 'horizontal');

    % 右：前向半盘（朝向未知，±90°）
    ax2 = nexttile(t);
    hold(ax2, 'on');
    H.poly(ax2, D.half_disk, pick_color(S, 'accent'), 0.30, 'none', 0.5);
    H.circle(ax2, [0 0.5], 0.85, pick_color(S, 'muted'), 0.9, '-');
    plot(ax2, [0 0], [0.5 - 0.85, 0.5 + 0.85], '--', ...
         'Color', pick_color(S, 'accent'), 'LineWidth', 1.0);
    H.arrow(ax2, [0 0.5], [0.85 0.5], pick_color(S, 'accent'));
    text(ax2, 0.425, 0.30, D.radius_label, 'HorizontalAlignment', 'center', ...
         'Interpreter', 'none');
    text(ax2, 0.0, 1.55, D.heading_label, 'HorizontalAlignment', 'center', ...
         'Interpreter', 'none');
    hold(ax2, 'off');
    axis(ax2, 'equal');
    xlim(ax2, [-1.15 1.35]);
    ylim(ax2, [-0.55 1.75]);
    axis(ax2, 'off');

    fig_save(fig, S, 'geo-q4-minimum-cover-31-points.png');
end