feat(rust): chat titles, BetterChat group styles, the voice and popups (phase 17)

PLAN.md §33, D134-D143. Protocol 12.

- Chat titles (D135-D137): per-server rules (stat, top N, text, colour)
  that rank the current wipe, and a mode (first | all | up to N). Worked
  out once in model/titles and read three ways: pushed whole to the game by
  a new titleSync loop (on change, restart or wipe), and on every
  leaderboard row as `titles`. Admin: PUT /servers/:id/titles.
- Group styles (D138, D139): a site group may carry all twelve BetterChat
  fields (rust_perm_group_chat). They ride perm.sync with `expect` from the
  pushed ledger, which gains a value column; a field changed in game is a
  `chat-field` drift row with the game's value, adopted into the style or
  put back. A withdrawn style is one `chat-group` retirement, never for
  `default`, cleared from the ledger only once BetterChat removed it.
- The voice (D140): one fleet setting naming a styled group; news and
  rust.announce chat lines carry its format and the plugin says them with
  no sender. Admin: GET/PUT /voice.
- Popups (D141, D142): rust.announce gains `delivery` (still version 1,
  from rust.options.delivery); each server gains news_delivery beside the
  news switch; `popup-unavailable` is not retried.
- GET /servers/:id/integrations reads, live, which optional mods a server
  has loaded. README lists BetterChat and PopupNotifications as optional.

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

client/test/format.test.js

@@ -11,7 +11,7 @@
 import test from 'node:test'
 import assert from 'node:assert/strict'
 
-import { ago, clock, count, day, duration, nextWipe, prefab, shortId } from '../src/lib/format.js'
+import { ago, clock, contrastInk, count, day, duration, nextWipe, prefab, shortId } from '../src/lib/format.js'
 
 const NOW = Date.parse('2026-09-16T12:00:00Z')
 
@@ -107,3 +107,11 @@ test('the next wipe: the reader’s own clock, how far away, and whether it move
   assert.equal(nextWipe(null, now), null)
   assert.equal(nextWipe({ at: 'soon', source: 'rule' }, now), null)
 })
+
+test('a title chip’s ink is whichever of black and white reads on its colour', () => {
+  assert.equal(contrastInk('#ffff00'), '#000000')
+  assert.equal(contrastInk('#FFAA55'), '#000000')
+  assert.equal(contrastInk('#1a1a8c'), '#ffffff')
+  assert.equal(contrastInk('#ff0000'), '#000000')
+  assert.equal(contrastInk('red'), '#000000', 'not a hex colour: black, on the caller’s fallback')
+})