设置页加「运行并发」一节：全站同时运行的上限，交互、应用、定时、系统四类各自的上限和优先级，旁边写各类现在在执行、在等名额的个数（/system 的 cluster.runs）；管理员可改，搭建者只读，自己读写 concurrency 一组、带离开前确认（同评测那一节）

frontend/src/pages/ConcurrencySettings.tsx

@@ -0,0 +1,145 @@
+import { useEffect, useState } from 'react'
+import { api } from '../api/client'
+import { Field, Notice, SectionBar, Spinner, confirmDialog } from '../components/ui'
+import { errorMessage } from '../lib/errors'
+import { useLeaveGuard } from '../lib/leave'
+import { CONCURRENCY_CLASSES, CONCURRENCY_TEXT } from '../lib/termsConcurrency'
+import { atLeast, usePrincipal } from '../store/auth'
+
+const T = CONCURRENCY_TEXT
+type Klass = (typeof CONCURRENCY_CLASSES)[number]
+interface Draft { total: string; limits: Record<Klass, string>; priorities: Record<Klass, string> }
+type Now = Partial<Record<Klass, { running?: number; waiting?: number }>>
+
+const draftOf = (group: Record<string, any> | undefined): Draft => ({
+  total: group?.max_total == null ? '' : String(group.max_total),
+  limits: Object.fromEntries(CONCURRENCY_CLASSES.map((k) => [k, String(group?.classes?.[k]?.limit ?? '')])) as Record<Klass, string>,
+  priorities: Object.fromEntries(CONCURRENCY_CLASSES.map((k) => [k, String(group?.classes?.[k]?.priority ?? '')])) as Record<Klass, string>,
+})
+
+const changedCount = (a: Draft, b: Draft): number =>
+  (a.total.trim() !== b.total ? 1 : 0)
+  + CONCURRENCY_CLASSES.filter((k) => a.limits[k].trim() !== b.limits[k]).length
+  + CONCURRENCY_CLASSES.filter((k) => a.priorities[k].trim() !== b.priorities[k]).length
+
+/**
+ * 设置页「偏好设置」里「运行并发」一节（docs/design/orchestration-round §5 W2-b）：全站总上限，交互、应用、定时、系统四类各自的
+ * 上限和优先级，旁边写各类现在在跑、在等几个（/system 的 cluster.runs）。
+ *
+ * 自己读、自己存（PUT /settings 只带 concurrency 一组），带自己的离开前确认，同评测那一节的做法。搭建者只读、管理员写
+ */
+export function ConcurrencySettingsSection() {
+  const me = usePrincipal()
+  const admin = atLeast(me, 'admin')
+  const [saved, setSaved] = useState<Draft | null>(null)
+  const [draft, setDraft] = useState<Draft | null>(null)
+  const [now, setNow] = useState<Now | null>(null)
+  const [loadError, setLoadError] = useState<unknown>(null)
+  const [saving, setSaving] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+  const [flash, setFlash] = useState(false)
+
+  const loadNow = () => api.system().then((s) => setNow(s?.cluster?.runs?.classes ?? null), () => setNow(null))
+  useEffect(() => {
+    api.settings.get().then((v) => {
+      setSaved(draftOf(v?.concurrency))
+      setLoadError(null)
+    }, setLoadError)
+    void loadNow()
+  }, [])
+
+  const cur = draft ?? saved
+  const changed = !!(cur && saved) && changedCount(cur, saved) > 0
+  useLeaveGuard(changed && !saving, () => confirmDialog({
+    title: T.leaveTitle(cur && saved ? changedCount(cur, saved) : 0),
+    consequences: T.leaveConsequences, confirmLabel: T.discard, danger: true,
+  }))
+
+  const save = async () => {
+    if (!cur || !changed) return
+    setSaving(true)
+    setError(null)
+    try {
+      const value = {
+        max_total: Number(cur.total.trim()),
+        classes: Object.fromEntries(CONCURRENCY_CLASSES.map((k) => [k, {
+          limit: Number(cur.limits[k].trim()), priority: Number(cur.priorities[k].trim()),
+        }])),
+      }
+      const out = await api.settings.put({ concurrency: value })
+      setSaved(draftOf(out?.concurrency ?? value))
+      setDraft(null)
+      setFlash(true)
+      setTimeout(() => setFlash(false), 1600)
+      void loadNow()
+    } catch (e) {
+      setError(errorMessage(e))
+    } finally {
+      setSaving(false)
+    }
+  }
+
+  if (loadError || !cur) return null
+  const edit = (patch: Partial<Draft>) => {
+    setError(null)
+    setDraft({ ...cur, ...patch, limits: { ...cur.limits, ...(patch.limits ?? {}) },
+               priorities: { ...cur.priorities, ...(patch.priorities ?? {}) } })
+  }
+  return (
+    <section data-concurrency-settings="">
+      <SectionBar title={T.title} hint={T.hint} />
+      <fieldset disabled={!admin || saving} className="m-0 min-w-0 space-y-3 border-0 p-0">
+        <Field label={T.maxTotal} htmlFor="pref-concurrency-total">
+          {(p) => (
+            <input {...p} className="field tnum max-w-40" inputMode="numeric" value={cur.total}
+                   onChange={(e) => edit({ total: e.target.value })} data-concurrency-setting="max_total" />
+          )}
+        </Field>
+        <div className="space-y-2">
+          {CONCURRENCY_CLASSES.map((k) => {
+            const info = T.classes[k]
+            const live = now?.[k]
+            return (
+              <div key={k} className="grid grid-cols-[8rem_1fr_1fr] items-end gap-3 max-sm:grid-cols-1" data-concurrency-class={k}>
+                <div className="text-xs">
+                  <div>{info.label}</div>
+                  <div className="text-2xs leading-relaxed text-faint">{info.hint}</div>
+                  {live && <div className="text-2xs text-dim" data-concurrency-now={k}>{T.now(live.running ?? 0, live.waiting ?? 0)}</div>}
+                </div>
+                <Field label={T.limit} htmlFor={`pref-concurrency-${k}-limit`}>
+                  {(p) => (
+                    <input {...p} className="field tnum max-w-32" inputMode="numeric" value={cur.limits[k]}
+                           onChange={(e) => edit({ limits: { [k]: e.target.value } as Record<Klass, string> })}
+                           data-concurrency-setting={`${k}.limit`} />
+                  )}
+                </Field>
+                <Field label={T.priority} htmlFor={`pref-concurrency-${k}-priority`} hint={k === 'interactive' ? T.priorityHint : undefined}>
+                  {(p) => (
+                    <input {...p} className="field tnum max-w-32" inputMode="numeric" value={cur.priorities[k]}
+                           onChange={(e) => edit({ priorities: { [k]: e.target.value } as Record<Klass, string> })}
+                           data-concurrency-setting={`${k}.priority`} />
+                  )}
+                </Field>
+              </div>
+            )
+          })}
+        </div>
+      </fieldset>
+      {!admin && <p className="mt-2 text-2xs text-faint">{T.readOnly}</p>}
+      {error && <Notice tone="err" className="mt-2" attr={{ 'data-concurrency-settings-error': '' }}>{error}</Notice>}
+      {admin && (changed || flash) && (
+        <div className="mt-3 flex items-center justify-end gap-2" data-concurrency-settings-bar="">
+          {flash && !changed && <span className="text-2xs text-[var(--st-done)]">{T.saved}</span>}
+          {changed && (
+            <>
+              <button type="button" className="btn btn-sm" onClick={() => { setDraft(null); setError(null) }} disabled={saving}>{T.discard}</button>
+              <button type="button" className="btn btn-primary btn-sm" onClick={() => void save()} disabled={saving} data-concurrency-settings-save="">
+                {saving && <Spinner size={11} />} {saving ? T.saving : T.save}
+              </button>
+            </>
+          )}
+        </div>
+      )}
+    </section>
+  )
+}

frontend/src/pages/SettingsPage.tsx

@@ -34,6 +34,7 @@ import {
 } from './VerifySettings'
 import { DraftModelSection } from './DraftModelSettings'
 import { EvalSettingsSection } from './EvalSettings'
+import { ConcurrencySettingsSection } from './ConcurrencySettings'
 import { GeneralTab } from './settings/GeneralTab'
 import { IdentityTab } from './settings/IdentityTab'
 import { NotifyTab } from './settings/NotifyTab'
@@ -1204,6 +1205,8 @@ function PrefsTab() {
 
           {values.eval && <EvalSettingsSection />}
 
+          {values.concurrency && <ConcurrencySettingsSection />}
+
           {values.ledger && <LedgerSection cur={ledgerCur} errors={ledgerErrs} onEdit={editLedger} />}
 
           {values.catalog_draft && (