fix(rust): nothing names who is online by default

The org lead's rule, settled 2026-09-22: who is online is always the
narrowest audience - staff - unless an operator deliberately widens it,
and a count is fine where a list of names is not.

The public site broke that in three places since phase 4. The Online
tab named every player, the feed carried joins, respawns, deaths, chat
and tallies, and the leaderboard's lastSeen - refreshed every minute by
a gather tally - said who was on as plainly as either. All three now
sit behind one setting:

* PRESENCE_KINDS, a subset of the public allowlist, gated per request.
  Below the audience the feed keeps the server's own story (wipe, start,
  shutdown) and says presenceHidden rather than looking quiet.
* the Online route answers { players: [], hidden, count, audience } -
  same shape, so an older client renders empty rather than breaking.
* rungs staff / signed_in / public, fleet-wide default in a new
  rust_settings table with an optional per-server override on
  rust_servers; an unknown stored word narrows to staff.
* the viewer's standing is RE-READ from the users row (ctx.users.getById),
  not taken from the token, so a demotion or a ban applies on the next
  request. Walked: a moderator demoted mid-session lost the roll call on
  the same cookie.
* per-viewer answers are Cache-Control: private, no-store.
* GET/PUT /admin/rust/visibility (requireRole admin) and an admin page,
  Rust visibility; every save is one activity-log row.

The browser walk also found every empty state in this module rendering
as a blank box. Core's EmptyState renders children only; this module
passed title/message (the shape the Integration Kit template teaches)
and React dropped both without a word. Fixed module-side with a small
Empty wrapper - nothing core or module-uo renders changes - and a client
test that refuses a titled EmptyState or a PageHeader subtitle.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

client/src/routes/admin/Visibility.jsx

@@ -0,0 +1,196 @@
+// ── Admin · Rust · Visibility ─────────────────────────────────────────────
+//
+// Who may see who is online. The org lead's rule (2026-09-22): nothing names who
+// is online by default — the narrowest audience, staff, unless an operator
+// deliberately widens it here. A count of players is public at every setting.
+//
+// One fleet default and an optional override per server, because a creative or
+// PvE server may reasonably publish a roll call a PvP server must not — and a
+// server that has not chosen follows the fleet, so narrowing the fleet narrows
+// every server that never said otherwise.
+//
+// The page says what "who is online" covers, because it is wider than the tab
+// of the same name: the killfeed, chat and joins in the feed, and the
+// leaderboard's "last seen" all name a player who was on at a given moment.
+
+import { useCallback, useEffect, useState } from 'react'
+
+import { ErrorState, Loading, useAsync } from '../../core.js'
+import api from '../../api.js'
+
+const INHERIT = ''
+
+const LABEL = {
+  staff: 'Staff only',
+  signed_in: 'Signed-in members',
+  public: 'Everyone',
+}
+
+const DESCRIBE = {
+  staff: 'Admins and moderators. The default.',
+  signed_in: 'Anybody with an account on this site.',
+  public: 'Anybody at all, signed in or not.',
+}
+
+function Card({ title, subtitle, children }) {
+  return (
+    <section className="panel" style={{ padding: '16px 18px', marginBottom: 18 }}>
+      <header style={{ display: 'flex', alignItems: 'baseline', gap: 12, marginBottom: 12 }}>
+        <h2 className="display" style={{ fontSize: '1.05rem', margin: 0, color: 'var(--head)' }}>
+          {title}
+        </h2>
+        {subtitle && (
+          <span className="sans dim" style={{ fontSize: '0.76rem' }}>
+            {subtitle}
+          </span>
+        )}
+      </header>
+      {children}
+    </section>
+  )
+}
+
+function AudienceSelect({ value, onChange, audiences, inherit = null, label }) {
+  return (
+    <select value={value} onChange={(e) => onChange(e.target.value)} style={selectStyle} aria-label={label}>
+      {inherit && <option value={INHERIT}>{inherit}</option>}
+      {audiences.map((a) => (
+        <option key={a} value={a}>{LABEL[a] || a}</option>
+      ))}
+    </select>
+  )
+}
+
+export default function Visibility() {
+  const [reloads, setReloads] = useState(0)
+  const { data, error: loadError } = useAsync(() => api.adminVisibility.read(), [reloads])
+
+  const [fleet, setFleet] = useState('staff')
+  const [servers, setServers] = useState({})
+  const [busy, setBusy] = useState(false)
+  const [error, setError] = useState('')
+  const [saved, setSaved] = useState(false)
+
+  // The form starts from what the server said and is reset from it after every
+  // save — the answer to a PUT is the new state, so what is on screen is always
+  // the site's word rather than what this page sent.
+  const load = useCallback((state) => {
+    setFleet(state.presence.fleet)
+    setServers(Object.fromEntries(state.presence.servers.map((s) => [s.id, s.override || INHERIT])))
+  }, [])
+
+  useEffect(() => {
+    if (data) load(data)
+  }, [data, load])
+
+  if (loadError) return <ErrorState error={loadError} />
+  if (!data) return <Loading />
+
+  const audiences = data.audiences
+  const rows = data.presence.servers
+
+  const dirtyFleet = fleet !== data.presence.fleet
+  const dirtyServers = rows.filter((s) => (servers[s.id] ?? INHERIT) !== (s.override || INHERIT))
+  const dirty = dirtyFleet || dirtyServers.length > 0
+
+  const effective = (id) => servers[id] || fleet
+  const widened = fleet !== 'staff' || rows.some((s) => effective(s.id) !== 'staff')
+
+  const save = async (e) => {
+    e.preventDefault()
+    setBusy(true)
+    setError('')
+    setSaved(false)
+    try {
+      const body = {}
+      if (dirtyFleet) body.fleet = fleet
+      if (dirtyServers.length) {
+        body.servers = Object.fromEntries(dirtyServers.map((s) => [s.id, servers[s.id] || null]))
+      }
+      load(await api.adminVisibility.save(body))
+      setSaved(true)
+      setReloads((n) => n + 1)
+    } catch (err) {
+      setError(err.message || 'That did not save.')
+    } finally {
+      setBusy(false)
+    }
+  }
+
+  return (
+    <form onSubmit={save} style={{ maxWidth: 900 }}>
+      <p className="sans dim" style={{ fontSize: '0.82rem', marginTop: 0 }}>
+        Nothing on this site names who is online unless you choose to show it. That covers more than
+        the Online tab: the joins, deaths and chat in each server’s feed, and the leaderboard’s “last
+        seen”, all say that a named player was on at a given moment. How many players are online is
+        always shown.
+      </p>
+
+      <Card title="Who is online" subtitle="the default for every server">
+        <div className="sans" style={{ display: 'flex', alignItems: 'center', gap: 12, fontSize: '0.86rem' }}>
+          <AudienceSelect value={fleet} onChange={setFleet} audiences={audiences} label="Fleet default" />
+          <span className="dim" style={{ fontSize: '0.78rem' }}>{DESCRIBE[fleet]}</span>
+        </div>
+      </Card>
+
+      <Card title="Per server" subtitle="an override, or the default above">
+        {rows.length === 0 && (
+          <p className="sans dim" style={{ fontSize: '0.82rem', margin: 0 }}>No servers are configured yet.</p>
+        )}
+        {rows.map((s) => (
+          <div
+            key={s.id}
+            className="sans"
+            style={{
+              display: 'flex',
+              alignItems: 'center',
+              gap: 12,
+              padding: '8px 0',
+              borderTop: '1px solid var(--line-soft)',
+              fontSize: '0.86rem',
+            }}
+          >
+            <span style={{ minWidth: 180, color: 'var(--head)' }}>
+              {s.name}
+              {!s.enabled && <span className="dim" style={{ fontSize: '0.74rem' }}> · disabled</span>}
+            </span>
+            <AudienceSelect
+              value={servers[s.id] ?? INHERIT}
+              onChange={(v) => setServers((prev) => ({ ...prev, [s.id]: v }))}
+              audiences={audiences}
+              inherit={`Default (${LABEL[fleet] || fleet})`}
+              label={`Who is online on ${s.name}`}
+            />
+            <span className="dim" style={{ fontSize: '0.78rem' }}>
+              {servers[s.id] ? 'its own setting' : 'follows the default'}
+            </span>
+          </div>
+        ))}
+      </Card>
+
+      {widened && (
+        <p className="sans" style={{ color: '#d08a2a', fontSize: '0.8rem' }}>
+          Wider than staff: on a PvP server, knowing who is on tells a raiding party whose base is
+          undefended.
+        </p>
+      )}
+
+      <div className="sans" style={{ display: 'flex', alignItems: 'center', gap: 12 }}>
+        <button type="submit" className="btn" disabled={busy || !dirty}>
+          {busy ? 'Saving…' : 'Save'}
+        </button>
+        {saved && !dirty && <span className="dim" style={{ fontSize: '0.8rem' }}>Saved.</span>}
+        {error && <span style={{ color: '#d08a2a', fontSize: '0.8rem' }}>{error}</span>}
+      </div>
+    </form>
+  )
+}
+
+const selectStyle = {
+  background: 'var(--panel-flat, transparent)',
+  color: 'var(--text)',
+  border: '1px solid var(--line)',
+  borderRadius: 'var(--radius-input, 6px)',
+  padding: '4px 8px',
+  fontSize: '0.84rem',
+}