feat: 适配 kimi-code 0.40.1 —— flag 清单/优先级语义/危险命令守卫

- flag 清单 9→10：新增 file_history、search_worker；secondary-model
  0.40.1 起默认开启（defaultEnabled）
- env 探测补齐为 12 项元组（10 flag + master + legacy），修正此前
  tower/subagent_fork/wait_for/auto_session_title 四项漏探
- 优先级语义跟随上游 flagService：单 flag env > [experimental] 显式值
  > master env（仅强制开）> 默认。master env 不再锁定 UI；setExperimentalFlag
  增加 explicitFalse 路径，关闭默认开/master 强开的 flag 时写字面 false
- 权限设置新增 dangerous_command_guard 开关（默认开，写 [permission]
  蛇形键；env KIMI_CODE_DANGEROUS_COMMAND_GUARD 运行时覆盖 config）
- 新增 11 个测试（注册表/写语义/守卫读写）

src/components/AgentSettingsPanel.tsx

@@ -157,6 +157,25 @@ export function AgentSettingsPanel({ rawOther, onChange }: AgentSettingsPanelPro
       </Card>
 
       <Card title={t("permissionRules")}>
+        {/* kimi-code 0.40.1 `[permission] dangerous_command_guard`. The env
+            var KIMI_CODE_DANGEROUS_COMMAND_GUARD (literal "true"/"false")
+            outranks this config at runtime; no env-lock UI here (deliberate
+            minimal scope). Absent key = upstream default on. */}
+        <Checkbox
+          label={t("permissionDangerousGuard")}
+          checked={settings.permission?.dangerous_command_guard ?? true}
+          onChange={(checked) =>
+            update({
+              permission: {
+                ...settings.permission,
+                dangerous_command_guard: checked,
+              },
+            })
+          }
+        />
+        <p className="text-xs text-content-muted">
+          {t("permissionDangerousGuardDesc")}
+        </p>
         <div className="space-y-2">
           {(settings.permission?.rules ?? []).map((rule, idx) => (
             <div key={idx} className="flex items-center gap-2">