feat(protocol2): house registry board (Part B ph.3)

Overlay BridgeHousing (new): a diff sweep over BaseHouse.AllHouses ->
house.update / house.remove (owner, region, location, decay level, co-owners,
friends, placement price), complementing the existing house.decay transition
feed. HousingSweepSeconds (300s); wired into [bridge reload|sweepnow|status.
Stock ServUO has no "for sale" flag, so this is an owner->houses registry;
price is the placement value, not a listing.

Sidecar: houses board table with upsert/delete/all; main routes house.update/
remove into it; GET /houses served from the store.

Docs: INTEGRATION.md house.* events + /houses endpoint; PROTOCOL_2 ph.3 built.

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

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

sidecar/src/web.rs

@@ -78,6 +78,7 @@ pub async fn serve(addr: &str, state: AppState) -> anyhow::Result<()> {
         .route("/guilds", get(guilds))
         .route("/governors", get(governors))
         .route("/online", get(online))
+        .route("/houses", get(houses))
         .route_layer(middleware::from_fn_with_state(state.clone(), gate));
 
     let app = Router::new()
@@ -730,6 +731,18 @@ async fn governors(State(st): State<AppState>) -> impl IntoResponse {
     }
 }
 
+/// The house registry: every house's latest snapshot (owner/region/location/decay/value). Served
+/// from the local board table, so it hydrates without the shard and survives an outage.
+async fn houses(State(st): State<AppState>) -> impl IntoResponse {
+    match st.store.houses_all().await {
+        Ok(houses) => (StatusCode::OK, Json(json!({"houses": houses}))),
+        Err(e) => (
+            StatusCode::INTERNAL_SERVER_ERROR,
+            Json(json!({"error": e.to_string()})),
+        ),
+    }
+}
+
 /// The current online population: total plus per-facet and per-region counts. This is the most
 /// recent `presence.online` snapshot from the event store (so it survives a sidecar restart); the
 /// live `presence.online` stream keeps it current, and `GET /history?kind=presence.online` gives the