Plans: add publish toggle action and UI

app/Http/Controllers/Admin/PlanController.php

@@ -219,6 +219,28 @@ class PlanController extends Controller
         return redirect()->back()->with('success', '套餐状态已更新：' . ($this->statusLabels()[$plan->status] ?? $plan->status));
     }
 
+    public function setPublished(Request $request, Plan $plan): RedirectResponse
+    {
+        $this->ensurePlatformAdmin($request);
+
+        $data = $request->validate([
+            'published' => ['required', Rule::in(['0', '1'])],
+        ]);
+
+        $published = (string) $data['published'] === '1';
+
+        if ($published) {
+            // 最小治理：发布动作仅写 published_at，不改变 status（避免误把草稿/停用套餐误启用）。
+            $plan->published_at = $plan->published_at ?? now();
+        } else {
+            $plan->published_at = null;
+        }
+
+        $plan->save();
+
+        return redirect()->back()->with('success', $published ? '套餐已发布' : '套餐已取消发布');
+    }
+
     public function update(Request $request, Plan $plan): RedirectResponse
     { 
         $this->ensurePlatformAdmin($request);