feat(admin): fully align the ban page with the reference theme

- submenu page title becomes 处理举报及禁封申诉 (menu title 举报&禁封申诉)
- replicate the reference pagenavi: first/prev/numbered/next/last links
  with displaying-num (每页 20 共N) and paging-input (第X页共Y页)
- report process form is now status-only like the reference theme:
  被举报用户/举报信息/被举报用户禁封信息/处理说明 blocks, with a 点击此处
  link to the restrictions tab (prefilled user_id) instead of an
  enforcement select
- replicate reference row details (举报用户/举报内容, 正在处理 state,
  此用户已解封 auto-close for stale appeals, 当前用户已解封 notice) and
  the table-box/preview-item style block
- drop now-unused ReportCenter::get_report_row

src/Messages/ReportCenter.php

@@ -159,20 +159,6 @@ class ReportCenter {
         return $result !== false;
     }
 
-    /**
-     * 获取单条举报原始行（ARRAY_A），不存在返回 null。
-     */
-    public function get_report_row(int $report_id): ?array {
-        $table = $this->table();
-        if ($table === '' || $report_id <= 0) {
-            return null;
-        }
-
-        global $wpdb;
-        $row = $wpdb->get_row($wpdb->prepare("SELECT * FROM {$table} WHERE id = %d", $report_id), ARRAY_A);
-        return $row ?: null;
-    }
-
     /**
      * 对举报目标执行处罚动作（REST 与原生后台共用入口）。
      *