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

server/test/events.test.js

@@ -60,7 +60,14 @@ test('a reader who does not say who they are gets the public view', async () =>
     await model.recent({ serverId: 'main' })
 
     assert.ok(!asked.kinds.includes('player.banned'), 'no IP-carrying kind by default')
-    assert.ok(asked.kinds.includes('player.death'))
+    // Nor anything naming a player who was on — the org lead's rule, and a caller
+    // that forgets to say what the viewer may see gets the narrowest answer.
+    assert.ok(!asked.kinds.includes('player.death'), 'no presence kind by default')
+    assert.ok(asked.kinds.includes('server.wipe'))
+
+    await model.recent({ serverId: 'main', presence: true })
+    assert.ok(asked.kinds.includes('player.death'), 'a viewer inside the presence audience gets the killfeed')
+    assert.ok(!asked.kinds.includes('player.banned'), 'presence never widens to staff kinds')
 
     await model.recent({ serverId: 'main', admin: true })
     assert.ok(asked.kinds.includes('player.banned'), 'an admin who says so gets them')
@@ -142,3 +149,24 @@ test('the leaderboard answers numbers, never nulls', async () => {
     db.leaderboard = original
   }
 })
+
+test('the leaderboard withholds lastSeen unless the viewer may see who is online', async () => {
+  withCore()
+
+  const db = require('../model/events/events.db')
+  const model = require('../model/events/events.model')
+  const original = db.leaderboard
+
+  db.leaderboard = async () => [{ steamId: '7656', name: 'A', kills: 3, lastSeen: '2026-09-22T10:00:00Z' }]
+
+  try {
+    const hidden = await model.leaderboard({ serverId: 'main' })
+    assert.equal('lastSeen' in hidden[0], false, 'absent, not null — null would read as "never seen"')
+    assert.equal(hidden[0].kills, 3)
+
+    const shown = await model.leaderboard({ serverId: 'main', presence: true })
+    assert.equal(shown[0].lastSeen, '2026-09-22T10:00:00Z')
+  } finally {
+    db.leaderboard = original
+  }
+})