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 A withdrawn style is one `chat-group` retirement, never for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

server/db/purge.sql

@@ -19,6 +19,11 @@
 -- it knows this module registered, because it is the side that knows which
 -- registrant owned what.
 
+-- Phase 17. `rust_perm_group_chat` before `rust_perm_groups`, which it
+-- references; the rest of this phase is columns, which go with their tables.
+DROP TABLE IF EXISTS rust_perm_group_chat;
+DROP TABLE IF EXISTS rust_title_rules;
+
 -- Phase 14.
 DROP TABLE IF EXISTS rust_map_overrides;
 DROP TABLE IF EXISTS rust_map_images;