feat(affiliate): attribution modes, settlement hardening, trusted proxies, QR and poster

- 归因模式可配置（first_touch/last_touch）、停佣开关、懒结算与佣金基数降级复查
- aksrt_get_client_ip 接入 aksrt_trusted_proxies 信任代理名单，防 CDN 头伪造
- 收益页 Canvas 二维码 + 750x1000 推广海报（本地打包 qrcode.min.js，无 CDN）
- 契约测试固化归因/海报/信任代理链路

inc/helpers/user-center-renderers/profile-revenue.php

@@ -145,6 +145,17 @@ $status_labels = [
                         <button type="button" class="btn-primary btn-sm" data-affiliate-copy><?php esc_html_e('复制', 'aksrt'); ?></button>
                         <small data-affiliate-feedback role="status" aria-live="polite"></small>
                     </div>
+                    <div class="uc-revenue-summary-row uc-revenue-summary-row--qr" data-affiliate-qr-row>
+                        <span><?php esc_html_e('推广二维码', 'aksrt'); ?></span>
+                        <div class="uc-revenue-qr">
+                            <canvas data-affiliate-qr width="148" height="148" aria-label="<?php esc_attr_e('推广链接二维码', 'aksrt'); ?>"></canvas>
+                            <div class="uc-revenue-qr__actions">
+                                <button type="button" class="btn-sm" data-affiliate-qr-download><?php esc_html_e('下载二维码', 'aksrt'); ?></button>
+                                <button type="button" class="btn-sm" data-affiliate-poster hidden><?php esc_html_e('生成推广海报', 'aksrt'); ?></button>
+                            </div>
+                            <small data-affiliate-qr-feedback role="status" aria-live="polite"></small>
+                        </div>
+                    </div>
                     <?php if ($affiliate_on) : ?><div class="uc-revenue-summary-row"><span><?php esc_html_e('佣金比例', 'aksrt'); ?></span><strong data-affiliate-ratio><?php echo esc_html((string) $commission_ratio); ?>%</strong></div><?php endif; ?>
                     <div class="uc-revenue-summary-row"><span><?php esc_html_e('推广人数', 'aksrt'); ?></span><div class="uc-revenue-count"><strong data-affiliate-promoters>—</strong><em><?php esc_html_e('人', 'aksrt'); ?></em></div></div>
                     <?php if ($affiliate_on) : ?>