feat(sub): opt-in dns and sniffer from remote Clash rules (#6868)

Public Mihomo templates ship rules, rule-providers and proxy-groups together
with a dns block those rules depend on (fake-ip ranges, nameserver policy).
Pasting a template inline keeps its dns, but pointing the global routing rules
at its URL dropped it, so URL users had to give up auto-refresh to keep it.

A new switch, subClashRemoteDNS (off by default), also takes the remote dns and
sniffer maps. It is opt-in because a remote dns block decides where clients send
every lookup. A malformed dns or sniffer value is skipped, not the whole template.
The component-test teardown now outlasts AntD Form's 10ms error debounce, which
otherwise fired after jsdom was gone.

frontend/src/pages/settings/SubscriptionGeneralTab.tsx

@@ -459,6 +459,16 @@ export default function SubscriptionGeneralTab({
                   onChange={(e) => updateSetting({ subClashRules: e.target.value })}
                 />
               </SettingListItem>
+              <SettingListItem
+                paddings="small"
+                title={t('pages.settings.subClashRemoteDNS')}
+                description={t('pages.settings.subClashRemoteDNSDesc')}
+              >
+                <Switch
+                  checked={allSetting.subClashRemoteDNS}
+                  onChange={(v) => updateSetting({ subClashRemoteDNS: v })}
+                />
+              </SettingListItem>
             </>
           ),
         },