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/router/public/rust.router.js

@@ -68,7 +68,7 @@ rustRouter.get(
   '/servers/:id/events',
   // #swagger.tags = ['Public · Rust']
   // #swagger.summary = 'Recent events on one Rust server'
-  // #swagger.description = 'The killfeed and everything else public that happened on a server, newest first. Narrow with `kind` (comma-separated) and `wipe`. Only publicly classified kinds are ever returned — moderation events, login attempts and anything carrying an IP address are stored but never served here.'
+  // #swagger.description = 'The killfeed and everything else public that happened on a server, newest first. Narrow with `kind` (comma-separated) and `wipe`. Only publicly classified kinds are ever returned — moderation events, login attempts and anything carrying an IP address are stored but never served here. Kinds that name a player who was on the server (connects, respawns, deaths, chat, tallies) are served only to viewers inside the operator’s presence audience, which defaults to staff; `presenceHidden` says when they were withheld.'
   // #swagger.parameters['id'] = { in: 'path', required: true, description: 'The server’s slug', schema: { type: 'string' } }
   // #swagger.parameters['kind'] = { in: 'query', required: false, description: 'One kind, or several comma-separated', schema: { type: 'string' } }
   // #swagger.parameters['wipe'] = { in: 'query', required: false, description: 'Restrict to one wipe id', schema: { type: 'string' } }
@@ -82,7 +82,7 @@ rustRouter.get(
   '/servers/:id/leaderboard',
   // #swagger.tags = ['Public · Rust']
   // #swagger.summary = 'The leaderboard for one Rust server'
-  // #swagger.description = 'Per-wipe when `wipe` is given, all-time otherwise. All-time is the per-wipe rows summed rather than a second set of counters, so a wipe splits a player’s history without ending it.'
+  // #swagger.description = 'Per-wipe when `wipe` is given, all-time otherwise. All-time is the per-wipe rows summed rather than a second set of counters, so a wipe splits a player’s history without ending it. `lastSeen` is withheld below the operator’s presence audience: a gather tally refreshes it every minute a player is on, so it would name who is online.'
   // #swagger.parameters['id'] = { in: 'path', required: true, description: 'The server’s slug', schema: { type: 'string' } }
   // #swagger.parameters['wipe'] = { in: 'query', required: false, description: 'Restrict to one wipe id', schema: { type: 'string' } }
   // #swagger.parameters['sort'] = { in: 'query', required: false, description: 'kills, deaths, npcKills or playtime', schema: { type: 'string' } }
@@ -107,9 +107,9 @@ rustRouter.get(
   '/servers/:id/online',
   // #swagger.tags = ['Public · Rust']
   // #swagger.summary = 'Who is on one Rust server right now'
-  // #swagger.description = 'Read from the presence board the bridge re-sends on every connect and every minute, rather than counted from connect and disconnect events — so it is correct even after the website has missed one.'
+  // #swagger.description = 'Read from the presence board the bridge re-sends on every connect and every minute, rather than counted from connect and disconnect events — so it is correct even after the website has missed one. **Nothing names who is online by default**: below the operator’s presence audience (staff unless widened) the names are withheld and only `count` is answered.'
   // #swagger.parameters['id'] = { in: 'path', required: true, description: 'The server’s slug', schema: { type: 'string' } }
-  /* #swagger.responses[200] = { description: 'Who is online' } */
+  /* #swagger.responses[200] = { description: 'Who is online — or, below the operator’s presence audience, only how many', content: { "application/json": { schema: { $ref: "#/components/schemas/RustOnline" } } } } */
   siteMode,
   servers.listOnline,
 )