V2.0.1: listen override fix, sing-box core fetch, probe settings page + fast report, spx removal, core mem env

- 0: sing-box gen overrides fragment listen/port from the inbound row
  (empty listen -> "::"), Update/Add recompute the stored fragment;
  non-loopback E2E against the real core binary.
- 1: agent fetches the sing-box core from the Gitea release when
  missing, self-checks it, and only then latches the switch.
- 2: node list shows the sing-box core version (heartbeat field,
  persisted on the node row), xray version as fallback.
- 3: public-page fallback returns 404 to anonymous visitors when the
  page is disabled.
- 4: settings restart hint bar removed, dead i18n keys cleaned.
- 5: two PUT calls missing JSON headers fixed (audit: only those two),
  batch probe-task creation endpoint + UI.
- 6: cf-probe retirement card and coverage pipeline removed.
- 7: generated vless links no longer carry spx (panel export + sub);
  parser still accepts spx; golden fixtures updated.
- probe batch: dedicated probe settings tab (public-page settings,
  tasks, per-node meta), retention_days editable, per-node traffic
  calibration + stat-interface pinning, runtime metrics split into a
  lightweight fast report (default 3s, 1-60s adjustable).
- 8: sing-box core processes start with GOMEMLIMIT=32MiB, GOGC=50.
- 9: dead /getTwoFactorEnable docs entries removed (frontend call and
  contract entry already gone at base; verified by grep).

frontend/src/pages/nodes/NodeList.tsx

@@ -493,10 +493,15 @@ export default function NodeList({
         render: (_value, record) => formatPct(record.memPct),
       },
       {
-        title: t('pages.nodes.xrayVersion'),
+        // Core version (V2.0.1 ②): agent rows run sing-box and show
+        // its version; traditional rows keep showing the xray one.
+        title: t('pages.nodes.coreVersion'),
         dataIndex: 'xrayVersion',
         align: 'center',
-        render: (_value, record) => record.xrayVersion || '-',
+        render: (_value, record) =>
+          record.nodeType === 'agent'
+            ? record.singboxVersion || record.xrayVersion || '-'
+            : record.xrayVersion || '-',
       },
       {
         title: t('pages.nodes.panelVersion') || 'Panel version',
@@ -840,8 +845,12 @@ export default function NodeList({
                   <Tag>{formatPct(statsNode.memPct)}</Tag>
                 </div>
                 <div className="stat-row">
-                  <span className="stat-label">{t('pages.nodes.xrayVersion')}</span>
-                  <Tag>{statsNode.xrayVersion || '-'}</Tag>
+                  <span className="stat-label">{t('pages.nodes.coreVersion')}</span>
+                  <Tag>
+                    {statsNode.nodeType === 'agent'
+                      ? statsNode.singboxVersion || statsNode.xrayVersion || '-'
+                      : statsNode.xrayVersion || '-'}
+                  </Tag>
                 </div>
                 <div className="stat-row">
                   <span className="stat-label">