fix(revenue): drop 待偿欠款 from the commission card

The field rendered in two places on /user/revenue/: the 我的佣金 card's
meta line and the 累计佣金 row, both gated on a non-zero balance. Remove
both, along with the now-unused $debt_amount local and the dead
.uc-commission-card__debt rule.

Source trace, since the label is only the surface: CommissionLedger::
overview() reads debt_minor from aksrt_commission_debt and returns it as
'debt'; record_debt() books the shortfall when a refund cannot be clawed
back in full, and repay_debt_from_pool() later clears it out of the
commission pool. That mechanism is untouched — arrears still accrue and
still get repaid, the UI just no longer surfaces them. The reference
theme's rebate card has no equivalent concept, so this is not a parity
target either.

Keep 'debt' in the template's overview() fallback array: it mirrors the
real return shape and the repayment path still depends on the value.

Add a contract test asserting the label, its class and the local are gone
from the display layer while overview() keeps returning the key; verified
it fails if the label is reintroduced.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

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

@@ -121,7 +121,6 @@ $status_labels = [
 $pool_amount = $format_amount($commission_stats['pool'] ?? 0);
 $total_amount = $format_amount($commission_stats['total'] ?? 0);
 $withdrawn_amount = $format_amount($commission_stats['withdrawn'] ?? 0);
-$debt_amount = $format_amount($commission_stats['debt'] ?? 0);
 $reward_panes = ['detail'];
 if ($affiliate_on) {
     $reward_panes[] = 'orders';
@@ -148,7 +147,6 @@ $pane_is_active = static function (string $tab) use ($active_reward_tab): bool {
                 <p class="uc-commission-card__meta">
                     <span><?php printf(esc_html__('累计佣金 ¥%s', 'aksrt'), esc_html($total_amount)); ?></span>
                     <span><?php printf(esc_html__('已提现 ¥%s', 'aksrt'), esc_html($withdrawn_amount)); ?></span>
-                    <?php if (($commission_stats['debt'] ?? '0.00') !== '0.00') : ?><span class="uc-commission-card__debt"><?php printf(esc_html__('待偿欠款 ¥%s', 'aksrt'), esc_html($debt_amount)); ?></span><?php endif; ?>
                 </p>
             </div>
             <?php if ($withdraw_on) : ?>
@@ -178,7 +176,7 @@ $pane_is_active = static function (string $tab) use ($active_reward_tab): bool {
                 </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) $commission_ratio); ?>%</strong></div>
-                <div class="uc-revenue-summary-row uc-revenue-summary-row--total"><span><?php esc_html_e('累计佣金', 'aksrt'); ?></span><div><strong><?php printf(esc_html__('累计 %s 元', 'aksrt'), esc_html($total_amount)); ?></strong><strong><?php printf(esc_html__('已提现 %s 元', 'aksrt'), esc_html($withdrawn_amount)); ?></strong><?php if (($commission_stats['debt'] ?? '0.00') !== '0.00') : ?><strong><?php printf(esc_html__('待偿欠款 %s 元', 'aksrt'), esc_html($debt_amount)); ?></strong><?php endif; ?></div></div>
+                <div class="uc-revenue-summary-row uc-revenue-summary-row--total"><span><?php esc_html_e('累计佣金', 'aksrt'); ?></span><div><strong><?php printf(esc_html__('累计 %s 元', 'aksrt'), esc_html($total_amount)); ?></strong><strong><?php printf(esc_html__('已提现 %s 元', 'aksrt'), esc_html($withdrawn_amount)); ?></strong></div></div>
                 <div class="uc-revenue-summary-row uc-revenue-summary-row--explain"><span><?php echo esc_html($details_title); ?></span><div class="uc-reward-richtext"><?php echo wp_kses_post(wpautop($details_text)); ?></div></div>
                 <?php endif; ?>
             </div>