feat: 上线前安全加固与发布工程化；appmall 由插件迁移为独立应用

安全（P0）
- 发布包签名：新增 scripts/package_keygen.php、scripts/package_verify.php、
  ywxapp\service\PackageVerifier；FrameworkService::apply() 解压前强制验签
  （ywxapp.framework_package_verify，默认开启）
- JWT 收紧：config/jwt.php 移除公开默认密钥，JwtService::assertStrongSecret()
  校验非空 / 长度≥32 / 已知弱值；.env.production.example 键名由 JWT_SECRET_KEY 修正为 JWT_SECRET
- /api/v1/Article：免登录白名单收窄为只读接口，写操作字段白名单 + assertOwner() 越权校验
- 开发者令牌：查找接口不再回显明文、统一失败文案 + 限流
- TemplateInstaller：文件名白名单 + realpath 归一化 + 目录内断言，修复 Zip Slip；补 use ZipArchive
- 后台登录：接入验证码、失败锁定与登录限流（config/ratelimit.php）
- 缓存 / Session 驱动可由 .env 覆盖（CACHE_DRIVER / SESSION_TYPE），集群部署改 redis
- paycenter 支付日志开关改为 PAY_LOG，不再跟随 APP_DEBUG

工程化 / 交付
- 新增 CHANGELOG.md 与 .env.production.example；composer.lock 入库锁定依赖版本
- 插件离线安装 CLI 增加 --uid，后台上传安装透传 uid，付费插件授权校验可通过
- 授权拒绝文案区分「未携带 uid」与「未找到有效授权」，便于排障
- .gitignore 放行 .env.production.example / .env.addon.example / .gitattributes / public/.htaccess

结构
- appmall 由 addon/appmall 迁移为独立应用 app/appmall（市场 / 开发者中心 / 审核 / 分润）

addon/articles/controller/backend/Dashboard.php

@@ -0,0 +1,75 @@
+<?php
+// +----------------------------------------------------------------------
+// | YwxApp [ WE CAN DO IT JUST THINK ]
+// +----------------------------------------------------------------------
+// | Copyright (c) 2026-2036 http://ywxapp.cn All rights reserved.
+// +----------------------------------------------------------------------
+// | Author: ywxapp<admin@ywxapp.cn>
+// +----------------------------------------------------------------------
+declare (strict_types = 1);
+
+namespace addon\articles\controller\backend;
+
+use addon\articles\library\ArticleSchema;
+use addon\articles\model\Article as ArticleModel;
+use addon\articles\model\ArticleCategory;
+use addon\articles\model\ArticleComment;
+use ywxapp\controller\BackendBase;
+
+/**
+ * 文章CMS 后台仪表盘（统计概览）
+ */
+class Dashboard extends BackendBase
+{
+    protected $noNeedVerify = [];
+
+    protected function initialize()
+    {
+        parent::initialize();
+        ArticleSchema::ensure();
+    }
+
+    public function index()
+    {
+        $today = strtotime('today');
+
+        $stats = [
+            'total'            => ArticleModel::count(),
+            'published'        => ArticleModel::where('status', 1)->count(),
+            'draft'            => ArticleModel::where('status', 0)->count(),
+            'pending'          => ArticleModel::scope('pending')->count(),
+            'today'            => ArticleModel::where('create_at', '>=', $today)->count(),
+            'views'            => (int) ArticleModel::sum('view_count'),
+            'comments'         => ArticleComment::count(),
+            'pending_comments' => ArticleComment::where('status', 0)->count(),
+            'trashed'          => ArticleModel::onlyTrashed()->count(),
+        ];
+
+        // 分类分布（Top 10）
+        $dist = [];
+        foreach (ArticleCategory::where('delete_at', 0)->order('sort', 'desc')->select() as $c) {
+            $dist[] = [
+                'id'    => $c->id,
+                'name'  => $c->name,
+                'count' => ArticleModel::where('cid', $c->id)->count(),
+            ];
+        }
+        usort($dist, function ($a, $b) {
+            return $b['count'] <=> $a['count'];
+        });
+        $dist = array_slice($dist, 0, 10);
+
+        // 热门文章 Top 10
+        $hot = ArticleModel::where('status', 1)
+            ->field('id,title,view_count,comment_count')
+            ->order('view_count', 'desc')
+            ->limit(10)
+            ->select();
+
+        return $this->view->fetch('dashboard/index', [
+            'stats' => $stats,
+            'dist'  => $dist,
+            'hot'   => $hot,
+        ]);
+    }
+}