feat(protocol2): guild and town-governor world-state streams (Part B ph.1)

Adds the first Part B streams from docs/PROTOCOL_2.md: guild rosters and
town governors ("mayors"), both outbound diff-board sweeps mirroring the
existing champ board.

Overlay:
- BridgeSocial (new): guild sweep+diff over BaseGuild.List -> guild.update /
  guild.remove (full-state upsert; disband detected via Disbanded), plus a
  real-time guild.join from EventSink.JoinGuild. (EventSink.CreateGuild is only
  the load-time factory, so creation is derived sidecar-side from a first-seen
  id, as champs do.)
- BridgeGovernance (new): city sweep over CityLoyaltySystem.Cities -> city.update
  (governor / governor-elect / election phase), gated on CityLoyaltySystem.Enabled.
- BridgeJson.Actor: shared serial/name/acct/webId/player writer used by both.
- BridgeConfig: GuildSweepSeconds (60s), CitySweepSeconds (300s).
- BridgeBoot: both wired into [bridge reload|sweepnow|status.

Sidecar:
- store: guilds + governors board tables with upsert/delete/all.
- main: route guild.update/remove and city.update into the boards.
- web: GET /guilds, GET /governors served from the store (snapshot-companion
  rule, so a fresh page or a restarted sidecar hydrates without the shard).

Docs: INTEGRATION.md event catalog (guild.*, city.update) + board endpoints;
PROTOCOL_2.md Part B phase 1 marked built.

Verified: sidecar cargo check clean; overlay compiles in the full ServUO
Scripts tree (0 errors, 0 warnings). Live end-to-end run still pending.

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

overlay/Config/Bridge.cfg

@@ -29,6 +29,16 @@ ChampSweepSeconds=10
 # support queue; the full open queue is also available on demand via pages.snapshot.
 PageSweepSeconds=5
 
+# Guild roster poll (docs/PROTOCOL_2.md Part B). Guilds expose only EventSink.JoinGuild, so
+# create/disband/leave/leader/alliance changes are found by diffing BaseGuild.List on this
+# interval (emit guild.update / guild.remove). Guild membership moves slowly; 60s is ample.
+GuildSweepSeconds=60
+
+# Town-governor poll. Each city's Governor / election is diffed on this interval to emit
+# city.update on change. Governors turn over on the order of weeks, so a slow sweep is fine.
+# Idle (emits nothing) unless the City Loyalty system is enabled (CityLoyalty.Enabled).
+CitySweepSeconds=300
+
 # Shown to a player when they run [link. The website page where they enter the code.
 LinkUrl=https://yoursite/link