feat(admin): 续费缺订阅治理闭环（订单手工绑定订阅）

resources/views/admin/platform_orders/show.blade.php

@@ -457,6 +457,16 @@
                             <a class="btn btn-secondary btn-sm" href="{!! $missingSubHelpUrlForRelationBlock !!}">去订阅管理查找订阅</a>
                         @endif
                     </div>
+
+                    <div class="mt-10">
+                        <form method="post" action="/admin/platform-orders/{{ $order->id }}/attach-subscription" class="inline-form" onsubmit="return confirm('确认将该订单绑定到所选订阅？该操作会写入审计留痕（meta.audit）');">
+                            @csrf
+                            <label class="muted" for="attach_site_subscription_id">绑定订阅ID</label>
+                            <input id="attach_site_subscription_id" name="site_subscription_id" type="number" min="1" class="input input-sm" placeholder="输入订阅ID" required>
+                            <button class="btn btn-primary btn-sm" type="submit">绑定订阅</button>
+                        </form>
+                        <div class="muted muted-xs mt-6">口径：仅用于“续费缺订阅”治理；系统将校验订阅的站点/套餐必须与当前订单一致，避免串单。</div>
+                    </div>
                 </div>
             </div>
         @endif