feat: add Selenium Settings page to configure paymentGroupId per office

Adds a new Settings → Advanced → Selenium Settings page where the office
name (paymentGroupId) used in United/DentalHub portal dropdowns can be
configured without touching code. Previously hardcoded as "Summit Dental
Care"; now injected from DB into the three United workers at job dispatch.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/Backend/src/routes/index.ts

@@ -44,6 +44,7 @@ import feeScheduleRoutes from "./feeSchedule";
 import licenseRoutes from "./license";
 import insuranceStatusBcbsMaRoutes from "./insuranceStatusBcbsMa";
 import labRxRoutes from "./lab-rx";
+import seleniumSettingsRoutes from "./selenium-settings";
 
 const router = Router();
 
@@ -92,5 +93,6 @@ router.use("/shopping-vendors", shoppingVendorsRoutes);
 router.use("/fee-schedule", feeScheduleRoutes);
 router.use("/license", licenseRoutes);
 router.use("/lab-rx", labRxRoutes);
+router.use("/selenium-settings", seleniumSettingsRoutes);
 
 export default router;