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/SeleniumService/helpers_dentaquest_eligibility.py

@@ -36,41 +36,34 @@ def make_session_entry() -> str:
 
 async def cleanup_session(sid: str, message: str | None = None):
     """
-    Close driver (if any), wake OTP waiter, set final state, and remove session entry.
-    Idempotent: safe to call multiple times.
+    Set final error state and wake OTP waiter. Schedules session removal after a delay
+    so the backend can read the actual error message before the session disappears.
     """
     s = sessions.get(sid)
     if not s:
         return
     try:
-        # Ensure final state
-        try:
-            if s.get("status") not in ("completed", "error", "not_found"):
-                s["status"] = "error"
-            if message:
-                s["message"] = message
-        except Exception:
-            pass
+        if s.get("status") not in ("completed", "error", "not_found"):
+            s["status"] = "error"
+        if message:
+            s["message"] = message
+    except Exception:
+        pass
 
-        # Wake any OTP waiter (so awaiting coroutines don't hang)
-        try:
-            ev = s.get("otp_event")
-            if ev and not ev.is_set():
-                ev.set()
-        except Exception:
-            pass
+    try:
+        ev = s.get("otp_event")
+        if ev and not ev.is_set():
+            ev.set()
+    except Exception:
+        pass
 
-        # NOTE: Do NOT quit driver - keep browser alive for next patient
-        # Browser manager handles the persistent browser instance
-
-    finally:
-        # Remove session entry from map
-        sessions.pop(sid, None)
+    # Keep session for 30s so backend can read the error, then remove
+    asyncio.create_task(_remove_session_later(sid, 30))
 
 
-async def _remove_session_later(sid: str, delay: int = 20):
+async def _remove_session_later(sid: str, delay: int = 30):
     await asyncio.sleep(delay)
-    await cleanup_session(sid)
+    sessions.pop(sid, None)
 
 
 async def start_dentaquest_run(sid: str, data: dict, url: str):