fix(report): fall back to schema defaults when the ban/report section was never saved

ban_settings()/report_settings() read the raw aksrt_settings option, so on
sites that never saved the ban/report admin section the keys are absent and
the preset reasons resolved to an empty list (frontend hard-coded fallback).
Read the section through SchemaProvider instead — read_section_settings
merges schema defaults, matching the reference theme _pz(key, default)
semantics. Also drop the dead user_report_categories parse chain that fed
a key nobody stores or consumes.

tests/widget-system/report-ban-contract.test.cjs

@@ -105,6 +105,12 @@ test('ban/report settings page mirrors the reference theme schema', () => {
   assert.match(runtime, /ban_settings\(\): array/)
   assert.match(runtime, /report_settings\(\): array/)
   assert.match(runtime, /user_report_s/)
+  // 缺键回退 schema 默认值（参考主题 _pz 语义）：运行时经 read_domain 读取，
+  // 裸 get_all() 会让未保存过分区的站点拿不到 ban_preset_reason 默认值。
+  assert.match(runtime, /read_domain\('users', 'report'\)/)
+  // 死链清理：user_report_categories 从不是真实存储键，解析器必须删除。
+  assert.ok(!runtime.includes('parse_report_categories'), 'dead parse_report_categories must stay removed')
+  assert.ok(!runtime.includes('user_report_categories'), 'dead user_report_categories key must stay removed')
   const appeal = read('src/User/BanAppeal.php')
   assert.match(appeal, /ban_appeal_keys/)
   assert.match(appeal, /ban_appeal_desc/)