feat(plans): 空库一键初始化默认套餐（带护栏与测试）

app/Http/Controllers/Admin/PlanController.php

@@ -228,6 +228,49 @@ class PlanController extends Controller
             });
     }
 
+    public function seedDefaults(Request $request): RedirectResponse
+    {
+        $this->ensurePlatformAdmin($request);
+
+        // 安全护栏：仅当当前库没有任何套餐时才允许一键初始化
+        $existingCount = Plan::query()->count();
+        if ($existingCount > 0) {
+            return redirect()->back()->with('error', '当前已有套餐（' . $existingCount . ' 条），为避免污染运营数据，已阻止一键初始化。');
+        }
+
+        $now = now();
+        $defaults = [
+            [
+                'code' => 'starter_monthly',
+                'name' => '基础版（月付）',
+                'billing_cycle' => 'monthly',
+                'price' => 99,
+                'list_price' => 129,
+                'status' => 'active',
+                'sort' => 10,
+                'description' => '适合刚开站的试运营阶段，可用于 Demo 场景。',
+                'published_at' => $now,
+            ],
+            [
+                'code' => 'pro_yearly',
+                'name' => '专业版（年付）',
+                'billing_cycle' => 'yearly',
+                'price' => 1999,
+                'list_price' => 2599,
+                'status' => 'active',
+                'sort' => 20,
+                'description' => '面向成长型站点，后续搭配授权项配置。',
+                'published_at' => $now,
+            ],
+        ];
+
+        foreach ($defaults as $row) {
+            Plan::query()->create($row);
+        }
+
+        return redirect('/admin/plans')->with('success', '已初始化默认套餐：' . count($defaults) . ' 条。');
+    }
+
     protected function statusLabels(): array
     {
         return [