feat(extensions): align Baidu push with reference theme

与参考主题（zibll）1:1 对齐百度推送，并清掉存量双路与死代码：

- 新增普通/快速收录通道开关，快速收录走 &type=daily；自动推送 JS 与参考实现一致

- 分类法 saved_term 推送（可推送类型推导公开分类法，排除 post_format，aksrt_baidu_push_taxonomies 可过滤）

- 推送结果写入 meta 去重，成功后不重复提交；编辑页 Metabox 展示结果并提供「重新提交」（nonce 校验后强制推送）

- 配置面收敛到扩展页单一 canonical 键：删除 SEO 页 seo_baidu_* 重复面与两处合并逻辑，不写迁移兜底

- 清理死代码：push_batch（零调用）及 batch_size、从不写入的 baidu_push_verified、零消费的熊掌号 xzh_* 七键；baidu_push_log_enabled 接入 log()

新增 PHP harness 驱动真实逻辑（通道/去重/重试/重新提交/术语/面板渲染）+ 参考主题契约测试；tests/admin 与 tests/widget-system 全量通过。

src/Admin/Schema/GlobalSchema.php

@@ -79,12 +79,6 @@ class GlobalSchema {
                             ['key' => 'ai_seo_keywords_prompt', 'label' => '关键词提示词', 'type' => 'textarea', 'default' => '', 'dependsOn' => ['key' => 'seo_ai_enabled', 'value' => true], 'help' => '留空使用内置默认。'],
                             ['key' => 'ai_seo_description_prompt', 'label' => '描述提示词', 'type' => 'textarea', 'default' => '', 'dependsOn' => ['key' => 'seo_ai_enabled', 'value' => true], 'help' => '留空使用内置默认。'],
                         ]],
-                        ['key' => 'baidu', 'title' => '百度SEO', 'fields' => [
-                            ['key' => 'seo_baidu_push', 'label' => '百度链接自动提交', 'type' => 'switch', 'default' => false],
-                            ['key' => 'seo_baidu_normal', 'label' => '百度普通收录', 'type' => 'switch', 'default' => false],
-                            ['key' => 'seo_baidu_fast', 'label' => '百度快速收录', 'type' => 'switch', 'default' => false],
-                            ['key' => 'seo_baidu_token', 'label' => '百度准入密钥Token', 'type' => 'input', 'default' => ''],
-                        ]],
                         ['key' => 'image', 'title' => '图片SEO', 'fields' => [
                             ['key' => 'seo_image_optimize', 'label' => '搜索引擎图片展示优化', 'type' => 'switch', 'default' => true],
                             ['key' => 'seo_image_default', 'label' => '默认图像', 'type' => 'media', 'default' => ''],

src/Admin/Schema/SchemaExtensionsPush.php

@@ -25,16 +25,11 @@ class SchemaExtensionsPush {
                     ['key' => 'baidu_push_on_publish', 'label' => '发布时主动推送', 'type' => 'switch', 'default' => true],
                     ['key' => 'baidu_push_on_update', 'label' => '更新时推送', 'type' => 'switch', 'default' => false],
                 ]],
-                ['key' => 'xzh', 'title' => '熊掌号 / JSON-LD', 'fields' => [
-                    ['key' => 'xzh_on', 'label' => '启用熊掌号', 'type' => 'switch', 'default' => false],
-                    ['key' => 'xzh_appid', 'label' => '百度 AppID', 'type' => 'input', 'default' => ''],
-                    ['key' => 'xzh_render_tail', 'label' => '文章底部显示熊掌号尾部', 'type' => 'switch', 'default' => true],
-                    ['key' => 'xzh_jsonld_single', 'label' => '文章页 JSON-LD', 'type' => 'switch', 'default' => true],
-                    ['key' => 'xzh_jsonld_page', 'label' => '页面 JSON-LD', 'type' => 'switch', 'default' => false],
-                    ['key' => 'xzh_jsonld_img', 'label' => '不添加图片', 'type' => 'switch', 'default' => false],
+                ['key' => 'channel', 'title' => '收录通道', 'fields' => [
+                    ['key' => 'baidu_push_normal', 'label' => '普通收录', 'type' => 'switch', 'default' => true],
+                    ['key' => 'baidu_push_fast', 'label' => '快速收录', 'type' => 'switch', 'default' => false],
                 ]],
                 ['key' => 'advanced', 'title' => '高级设置', 'fields' => [
-                    ['key' => 'baidu_push_batch_size', 'label' => '批量推送条数', 'type' => 'number', 'default' => 50, 'min' => 1, 'max' => 500],
                     ['key' => 'baidu_push_log_enabled', 'label' => '记录推送日志', 'type' => 'switch', 'default' => true],
                 ]],
             ],