feat: 插件依赖强制校验 + 文章后台表单/表格注入 hook

- PluginManager: requires 依赖链校验（enable 需依赖已启用，disable 阻止有启用依赖者的插件，boot 跳过依赖未满足插件），all() 输出依赖状态供后台展示
- Plugins 页：卡片显示依赖链徽章，依赖未满足时禁用启用按钮，启停失败弹错误通知
- PostResource: form()/table() 增加 filament.post_form / filament.post_table 注入点
- membership 插件：注入「付费设置」Section（meta.price 单篇价格 + meta.members_only 会员专享）与表格价格/会员列

app/Filament/Pages/Plugins.php

@@ -38,14 +38,22 @@ class Plugins extends Page
 
     public function enablePlugin(string $key): void
     {
-        app(PluginManager::class)->enable($key);
-        Notification::make()->title('已启用：'.$key)->success()->send();
+        try {
+            app(PluginManager::class)->enable($key);
+            Notification::make()->title('已启用：'.$key)->success()->send();
+        } catch (\Throwable $e) {
+            Notification::make()->title('启用失败')->body($e->getMessage())->danger()->send();
+        }
     }
 
     public function disablePlugin(string $key): void
     {
-        app(PluginManager::class)->disable($key);
-        Notification::make()->title('已停用：'.$key)->warning()->send();
+        try {
+            app(PluginManager::class)->disable($key);
+            Notification::make()->title('已停用：'.$key)->warning()->send();
+        } catch (\Throwable $e) {
+            Notification::make()->title('停用失败')->body($e->getMessage())->danger()->send();
+        }
     }
 
     public function uninstallPlugin(string $key): void