feat(xray): explain what mux concurrency means on xray-core 26.11.9

xray-core 26.11.9 (bb335c6) raises any mux concurrency from 0 to 128 to
128, where 0 used to mean 8 and every other value was used as written. The
panel's default of 8 and anything a user types up to 128 therefore no
longer changes the result on a current core, while an older client core
still honours it.

The concurrency field of the outbound mux form, the host mux override and
the JSON subscription mux settings now carries that as a hint in all 14
locales. The emitted value is unchanged.

frontend/src/pages/settings/SubscriptionFormatsTab.tsx

@@ -361,6 +361,7 @@ export default function SubscriptionFormatsTab({
                   <SettingListItem
                     paddings="small"
                     title={t('pages.settings.subFormats.concurrency')}
+                    description={t('pages.settings.subFormats.concurrencyHint')}
                   >
                     <InputNumber
                       value={muxObj.concurrency}

frontend/src/pages/xray/outbounds/transport/mux.tsx

@@ -26,6 +26,7 @@ export default function MuxForm({ protocol, network, flow = '' }: MuxFormProps)
         <>
           <FormField
             label={t('pages.settings.subFormats.concurrency')}
+            tooltip={t('pages.settings.subFormats.concurrencyHint')}
             name={['mux', 'concurrency']}
           >
             <InputNumber min={-1} max={1024} />