feat: apply inbound/outbound/routing changes live via Xray gRPC API

Add a hot-apply layer that computes a diff between the old and new
generated config and applies only the changed parts through the Xray
gRPC HandlerService and RoutingService, avoiding a full process restart
whenever possible. A restart is still performed when sections that have
no reload API (log, dns, policy, observatory, ...) actually change.

Key additions:
- internal/xray/hot_diff.go: ComputeHotDiff with canonical-JSON
  comparison (sorted keys, null=absent, full number precision) so UI
  reformatting never triggers a spurious restart
- internal/xray/api.go: AddOutbound/DelOutbound, ApplyRoutingConfig,
  GetBalancerInfo, SetBalancerTarget, TestRoute gRPC wrappers
- internal/web/service/xray.go: tryHotApply, ensureAPIServices,
  GetBalancersStatus, OverrideBalancer, TestRoute service methods
- internal/web/controller/xray_setting.go: balancerStatus,
  balancerOverride, routeTest API endpoints
- frontend: BalancersTab live-status/override columns, RouteTester
  component, Restart button removed (Save now hot-applies)
- balancer-helpers.ts: syncObservatories never creates observatory
  sections for random/roundRobin balancers (no reload API → restart)
- i18n: balancerLive/Override/routeTester keys added to all 13 locales

frontend/src/pages/xray/routing/RouteTester.tsx

@@ -0,0 +1,146 @@
+import { useState } from 'react';
+import { useTranslation } from 'react-i18next';
+import { Alert, Button, Col, Input, InputNumber, Row, Select, Space, Tag } from 'antd';
+import { AimOutlined } from '@ant-design/icons';
+
+import { HttpUtil } from '@/utils';
+
+interface RouteTesterProps {
+  inboundTags: string[];
+  isMobile: boolean;
+}
+
+// Mirror of the /xray/routeTest response (RoutingService.TestRoute).
+interface RouteTestResult {
+  matched: boolean;
+  outboundTag: string;
+  groupTags?: string[];
+}
+
+const PROTOCOL_OPTIONS = ['http', 'tls', 'quic', 'bittorrent'].map((p) => ({ label: p, value: p }));
+
+export default function RouteTester({ inboundTags, isMobile }: RouteTesterProps) {
+  const { t } = useTranslation();
+  const [dest, setDest] = useState('');
+  const [port, setPort] = useState<number | null>(443);
+  const [network, setNetwork] = useState('tcp');
+  const [inboundTag, setInboundTag] = useState<string | undefined>(undefined);
+  const [protocol, setProtocol] = useState<string | undefined>(undefined);
+  const [testing, setTesting] = useState(false);
+  const [result, setResult] = useState<RouteTestResult | null>(null);
+
+  async function run() {
+    const value = dest.trim();
+    if (!value) return;
+    // Domains never contain ':' and a pure dotted-quad is an IPv4 address;
+    // everything else is treated as a domain.
+    const isIp = /^(\d{1,3}\.){3}\d{1,3}$/.test(value) || value.includes(':');
+    setTesting(true);
+    setResult(null);
+    try {
+      const msg = await HttpUtil.post('/panel/api/xray/routeTest', {
+        domain: isIp ? '' : value,
+        ip: isIp ? value : '',
+        port: port ?? 0,
+        network,
+        inboundTag: inboundTag || '',
+        protocol: protocol || '',
+      });
+      if (msg?.success && msg.obj && typeof msg.obj === 'object') {
+        setResult(msg.obj as RouteTestResult);
+      }
+    } finally {
+      setTesting(false);
+    }
+  }
+
+  const fieldSpan = isMobile ? 24 : undefined;
+
+  return (
+    <Space orientation="vertical" size="middle" style={{ width: '100%' }}>
+      <Alert type="info" showIcon title={t('pages.xray.routeTesterDesc')} />
+      <Row gutter={[8, 8]} align="bottom">
+        <Col xs={fieldSpan} sm={7}>
+          <Input
+            placeholder={t('pages.xray.routeTesterDest')}
+            value={dest}
+            onChange={(e) => setDest(e.target.value)}
+            onPressEnter={run}
+            allowClear
+          />
+        </Col>
+        <Col xs={12} sm={3}>
+          <InputNumber
+            style={{ width: '100%' }}
+            min={0}
+            max={65535}
+            placeholder={t('pages.xray.routeTesterPort')}
+            value={port}
+            onChange={(v) => setPort(v)}
+          />
+        </Col>
+        <Col xs={12} sm={3}>
+          <Select
+            style={{ width: '100%' }}
+            value={network}
+            onChange={setNetwork}
+            options={[
+              { label: 'TCP', value: 'tcp' },
+              { label: 'UDP', value: 'udp' },
+            ]}
+          />
+        </Col>
+        <Col xs={12} sm={4}>
+          <Select
+            style={{ width: '100%' }}
+            placeholder={t('pages.xray.routeTesterInbound')}
+            allowClear
+            value={inboundTag}
+            onChange={setInboundTag}
+            options={inboundTags.filter(Boolean).map((tag) => ({ label: tag, value: tag }))}
+          />
+        </Col>
+        <Col xs={12} sm={4}>
+          <Select
+            style={{ width: '100%' }}
+            placeholder={t('pages.xray.routeTesterProtocol')}
+            allowClear
+            value={protocol}
+            onChange={setProtocol}
+            options={PROTOCOL_OPTIONS}
+          />
+        </Col>
+        <Col xs={fieldSpan} sm={3}>
+          <Button type="primary" icon={<AimOutlined />} loading={testing} disabled={!dest.trim()} onClick={run} block>
+            {t('pages.xray.routeTesterTest')}
+          </Button>
+        </Col>
+      </Row>
+
+      {result && (
+        result.matched ? (
+          <Alert
+            type="success"
+            showIcon
+            title={
+              <Space wrap>
+                <span>{t('pages.xray.routeTesterMatchedOutbound')}:</span>
+                <Tag color="blue">{result.outboundTag || '—'}</Tag>
+                {(result.groupTags || []).length > 0 && (
+                  <>
+                    <span>{t('pages.xray.routeTesterViaBalancer')}:</span>
+                    {(result.groupTags || []).map((tag) => (
+                      <Tag key={tag} color="orange">{tag}</Tag>
+                    ))}
+                  </>
+                )}
+              </Space>
+            }
+          />
+        ) : (
+          <Alert type="warning" showIcon title={t('pages.xray.routeTesterDefaultOutbound')} />
+        )
+      )}
+    </Space>
+  );
+}

frontend/src/pages/xray/routing/RoutingTab.tsx

@@ -1,10 +1,11 @@
 import { useCallback, useMemo, useRef, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { Button, Modal, Space, Table, Tabs } from 'antd';
-import { ControlOutlined, PlusOutlined, UnorderedListOutlined } from '@ant-design/icons';
+import { AimOutlined, ControlOutlined, PlusOutlined, UnorderedListOutlined } from '@ant-design/icons';
 
 import { catTabLabel } from '@/pages/settings/catTabLabel';
 import RoutingBasic from './RoutingBasic';
+import RouteTester from './RouteTester';
 import RuleFormModal from './RuleFormModal';
 import type { RoutingRule } from './RuleFormModal';
 import RuleCardList from './RuleCardList';
@@ -312,6 +313,11 @@ export default function RoutingTab({
               </Space>
             ),
           },
+          {
+            key: 'tester',
+            label: catTabLabel(<AimOutlined />, t('pages.xray.routeTester'), isMobile),
+            children: <RouteTester inboundTags={inboundTagOptions} isMobile={isMobile} />,
+          },
         ]}
       />
       <RuleFormModal