feat(admin): 订阅详情页补齐续费缺订阅治理入口（同站点/同套餐）

tests/Feature/AdminSiteSubscriptionShowRenewalMissingSubscriptionGovernanceLinkTest.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\Merchant;
+use App\Models\Plan;
+use App\Models\SiteSubscription;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class AdminSiteSubscriptionShowRenewalMissingSubscriptionGovernanceLinkTest extends TestCase
+{
+    use RefreshDatabase;
+
+    protected function loginAsPlatformAdmin(): void
+    {
+        $this->seed();
+
+        $this->post('/admin/login', [
+            'email' => 'platform.admin@demo.local',
+            'password' => 'Platform@123456',
+        ])->assertRedirect('/admin');
+    }
+
+    public function test_show_should_render_renewal_missing_subscription_governance_link(): void
+    {
+        $this->loginAsPlatformAdmin();
+
+        $merchant = Merchant::query()->firstOrFail();
+
+        $plan = Plan::query()->create([
+            'code' => 'sub_show_rms_link_plan',
+            'name' => '订阅详情 续费缺订阅治理入口测试套餐',
+            'billing_cycle' => 'monthly',
+            'price' => 10,
+            'list_price' => 10,
+            'status' => 'active',
+            'sort' => 10,
+            'published_at' => now(),
+        ]);
+
+        $sub = SiteSubscription::query()->create([
+            'merchant_id' => $merchant->id,
+            'plan_id' => $plan->id,
+            'status' => 'active',
+            'source' => 'manual',
+            'subscription_no' => 'SS_SHOW_RMS_LINK_0001',
+            'plan_name' => $plan->name,
+            'billing_cycle' => $plan->billing_cycle,
+            'period_months' => 1,
+            'amount' => 10,
+            'starts_at' => now(),
+            'ends_at' => now()->addMonth(),
+        ]);
+
+        $res = $this->get('/admin/site-subscriptions/' . $sub->id);
+        $res->assertOk();
+
+        $html = (string) $res->getContent();
+
+        $this->assertStringContainsString('查看续费缺订阅订单（同站点/同套餐）', $html);
+        $this->assertStringContainsString('/admin/platform-orders?', $html);
+        $this->assertStringContainsString('merchant_id=' . $merchant->id, $html);
+        $this->assertStringContainsString('plan_id=' . $plan->id, $html);
+        $this->assertStringContainsString('renewal_missing_subscription=1', $html);
+
+        // back 应回到订阅详情自身
+        $this->assertStringContainsString('back=' . urlencode('/admin/site-subscriptions/' . $sub->id), $html);
+    }
+}