feat(housekeeping): unify complete rebuild in gated preview

.env.example

@@ -17,9 +17,6 @@ NODE_ENV=production
 PORT=3002
 NEXT_TELEMETRY_DISABLED=1
 UV_THREADPOOL_SIZE=16
-# Non-production preview only; production always returns 404.
-HOUSEKEEPING_NEXT_PREVIEW_ENABLED=false
-
 # --- HOTEL & URLS ---
 HOTEL_NAME=EPIC WEB CONTROL
 APP_URL=http://localhost:3002
@@ -76,3 +73,6 @@ LOG_LEVEL=error
 
 # --- FLARESOLVERR (Cloudflare bypass for clone sources) ---
 FLARESOLVERR_URL=http://localhost:8191
+
+# Gated Housekeeping preview; never enabled in production
+HOUSEKEEPING_NEXT_PREVIEW_ENABLED=false