feat: wire Tufts SCO to DentaQuest portal and fix insurance credential dropdown

- Add /dentaquest-eligibility endpoint in Python agent (Tufts SCO uses providers.dentaquest.com)
- Add backend route, processor, and service client for Tufts SCO (separate from UnitedSCO/DentalHub)
- Fix Tufts SCO button to post to new tuftssco route instead of unitedsco
- Fix credential field names: dentaquestUsername/Password (was tuftsscoUsername/Password)
- Fix socket event: listen for selenium:dentaquest_session_started (was unitedsco)
- Fix error visibility: keep session alive 30s on error so backend reads real message
- Replace free-text Site Key field with dropdown to prevent key mismatches

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

apps/Backend/src/routes/index.ts

@@ -14,6 +14,7 @@ import insuranceStatusRoutes from "./insuranceStatus";
 import insuranceStatusDdmaRoutes from "./insuranceStatusDDMA";
 import insuranceStatusDeltaInsRoutes from "./insuranceStatusDeltaIns";
 import insuranceStatusUnitedSCORoutes from "./insuranceStatusUnitedSCO";
+import insuranceStatusTuftsSCORoutes from "./insuranceStatusTuftsSCO";
 import insuranceStatusCCARoutes from "./insuranceStatusCCA";
 import paymentsRoutes from "./payments";
 import databaseManagementRoutes from "./database-management";
@@ -41,6 +42,7 @@ router.use("/insurance-status", insuranceStatusRoutes);
 router.use("/insurance-status-ddma", insuranceStatusDdmaRoutes);
 router.use("/insurance-status-deltains", insuranceStatusDeltaInsRoutes);
 router.use("/insurance-status-unitedsco", insuranceStatusUnitedSCORoutes);
+router.use("/insurance-status-tuftssco", insuranceStatusTuftsSCORoutes);
 router.use("/insurance-status-cca", insuranceStatusCCARoutes);
 router.use("/payments", paymentsRoutes);
 router.use("/database-management", databaseManagementRoutes);