feat(mtproto): adopt dolonet/mtg-multi and make MTProto inbounds multi-client

Replace the upstream 9seconds/mtg sidecar with the dolonet/mtg-multi fork so a single MTProto inbound can serve many per-user secrets. Each panel client is now one named FakeTLS secret in the fork's [secrets] section: clients are first-class (attach/detach, limits, expiry, per-client tg:// links) exactly like every other protocol, mirroring the WireGuard multi-client model. Per-client traffic and online status come from the fork's /stats JSON API (its Prometheus output has no per-user label), fed into the existing email-keyed client_traffics accumulator; an optional throttle caps concurrent connections. A one-time seeder converts each legacy single-secret inbound into a one-client inbound.

The fork ships only linux/darwin amd64/arm64 binaries but is pure Go, so provisioning builds it from source for every supported platform (release.yml, DockerInit.sh) while keeping the panel-expected mtg-<os>-<arch> filename and the 'run' verb, so process.go is untouched. Also fixes a pre-existing update.sh gap that never renamed the mtg binary for armv6/armv7 updates.

frontend/src/pages/inbounds/form/protocols/mtproto.tsx

@@ -1,8 +1,6 @@
 import { useTranslation } from 'react-i18next';
-import { Button, Form, Input, InputNumber, Select, Space, Switch } from 'antd';
-import { ReloadOutlined } from '@ant-design/icons';
+import { Form, Input, InputNumber, Select, Switch } from 'antd';
 
-import { generateMtprotoSecret, mtprotoSecretForDomain } from '@/lib/xray/inbound-defaults';
 import { useOutboundTags } from '@/api/queries/useOutboundTags';
 
 export default function MtprotoFields() {
@@ -12,29 +10,12 @@ export default function MtprotoFields() {
   const { data: outboundTags } = useOutboundTags();
   return (
     <>
-      <Form.Item name={['settings', 'fakeTlsDomain']} label={t('pages.inbounds.form.fakeTlsDomain')}>
-        <Input
-          placeholder="www.cloudflare.com"
-          onChange={(e) => {
-            const current = (form.getFieldValue(['settings', 'secret']) as string) ?? '';
-            form.setFieldValue(['settings', 'secret'], mtprotoSecretForDomain(current, e.target.value));
-          }}
-        />
-      </Form.Item>
-      <Form.Item label={t('pages.inbounds.form.mtprotoSecret')}>
-        <Space.Compact block>
-          <Form.Item name={['settings', 'secret']} noStyle>
-            <Input readOnly style={{ width: 'calc(100% - 32px)' }} />
-          </Form.Item>
-          <Button
-            aria-label={t('regenerate')}
-            icon={<ReloadOutlined />}
-            onClick={() => {
-              const domain = form.getFieldValue(['settings', 'fakeTlsDomain']);
-              form.setFieldValue(['settings', 'secret'], generateMtprotoSecret(domain as string));
-            }}
-          />
-        </Space.Compact>
+      <Form.Item
+        name={['settings', 'fakeTlsDomain']}
+        label={t('pages.inbounds.form.fakeTlsDomain')}
+        tooltip={t('pages.inbounds.form.mtprotoFakeTlsDomainHint')}
+      >
+        <Input placeholder="www.cloudflare.com" />
       </Form.Item>
       <Form.Item
         name={['settings', 'domainFronting', 'ip']}
@@ -75,6 +56,13 @@ export default function MtprotoFields() {
       <Form.Item name={['settings', 'debug']} label={t('pages.inbounds.form.mtgDebug')} valuePropName="checked">
         <Switch />
       </Form.Item>
+      <Form.Item
+        name={['settings', 'throttleMaxConnections']}
+        label={t('pages.inbounds.form.mtgThrottleMaxConnections')}
+        tooltip={t('pages.inbounds.form.mtgThrottleMaxConnectionsHint')}
+      >
+        <InputNumber min={0} placeholder="0" style={{ width: '100%' }} />
+      </Form.Item>
       <Form.Item
         name={['settings', 'routeThroughXray']}
         label={t('pages.inbounds.form.mtgRouteThroughXray')}