fix(report): give preset reasons a stable non-empty slug for CJK labels

ban_settings() derived each reason slug via sanitize_key(label), which
strips CJK text to an empty string; the frontend filter then discarded
every reason (including the schema defaults) and fell back to the
hard-coded list. Derive the slug from an ASCII key when possible and
from a stable md5 short hash of the label otherwise, and relax the
frontend filter to the label only. Adds a WP-stub harness that verifies
the defaults path end to end (tests/dev/verify-ban-settings-defaults.php).

src/Settings/UserRuntime.php

@@ -216,14 +216,21 @@ class UserRuntime {
     public static function ban_settings(): array {
         $settings = self::read_report_section();
 
-        // 预置原因：group 数组 [{t:...}]（对齐参考主题）或旧版每行一条文本
+        // 预置原因：group 数组 [{t:...}]（对齐参考主题）或旧版每行一条文本。
+        // slug 不能用 sanitize_key(标签) 派生：中文标签会被清洗成空串，
+        // 导致前端按 slug 非空过滤后整列表被丢弃。改用标签内容的稳定短哈希
+        // （跨请求一致、可通过服务端 sanitize_key、ASCII 标签同样稳定）。
         $reasons_raw = $settings['ban_preset_reason'] ?? null;
         $reasons = [];
+        $reason_slug = static function (string $text): string {
+            $key = sanitize_key($text);
+            return $key !== '' ? $key : substr(md5($text), 0, 12);
+        };
         if (is_array($reasons_raw)) {
             foreach ($reasons_raw as $row) {
                 $text = trim((string) ($row['t'] ?? ''));
                 if ($text !== '') {
-                    $reasons[] = ['slug' => sanitize_key($text), 'name' => sanitize_text_field($text)];
+                    $reasons[] = ['slug' => $reason_slug($text), 'name' => sanitize_text_field($text)];
                 }
             }
         } else {
@@ -234,7 +241,7 @@ class UserRuntime {
                 }
                 $parts = explode('|', $line, 2);
                 $reasons[] = [
-                    'slug' => sanitize_key($parts[0]),
+                    'slug' => $reason_slug((string) ($parts[1] ?? $parts[0])),
                     'name' => sanitize_text_field($parts[1] ?? $parts[0]),
                 ];
             }