feat(shard): ingest Protocol 2.0 boards — guilds, governors, presence, houses

Phase 1 of the Protocol 2.0/2.1 integration: the read/ingest backend for the four
new uo-link boards, following the established champs/pages pattern (ingest → our
MariaDB + snapshot-on-reconnect + public SSE + token-free public endpoint).

- Schema: shard_guilds, shard_governors, shard_governor_terms, shard_presence;
  extend shard_houses with the house.update registry columns (owner_name,
  co_owners, friends, price, decay, in_registry) so the decay-transition and
  registry feeds share one house row without clobbering each other.
- Ingest: route guild.update/remove, city.update, presence.online,
  house.update/remove; log guild.join (real-time joins feed); region.enter is
  broadcast-only. All new public kinds added to the SSE allowlist.
- Governor term history captured from day one: on every observed governor CHANGE
  the open term is closed and a new one opened, idempotent so backfill/duplicate
  city.update never spawn spurious terms. votes stays NULL (the feed carries only
  candidate count, not tallies) — we never fabricate vote numbers.
- Client + backfill: getGuilds/getGovernors/getHouses/getPresence; snapshot each
  board on every WS (re)connect, independently guarded so an empty/failed board
  (e.g. no City Loyalty) never wipes another.
- Public endpoints: /shard/{guilds,governors,governors/:city/history,presence,houses}.
- Tests: ingest routing for all new kinds + governor term-capture idempotency
  (15 new; full suite 179/179). Swagger regenerated.

Refs .plans/protocol2-integration.md (Phase 1).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/src/utils/shardBroadcast.js

@@ -36,6 +36,15 @@ const PUBLIC_KINDS = new Set([
   // Champion-spawn board deltas — the public Champions page renders these live.
   'champ.update',
   'champ.remove',
+  // Protocol 2.0 boards — all public, rendered live on their respective pages.
+  'guild.update',
+  'guild.remove',
+  'guild.join',
+  'city.update',
+  'presence.online',
+  'region.enter',
+  'house.update',
+  'house.remove',
 ])
 
 // Open response streams per channel.