feat: add United Ucard claim worker and fix batch-column site-key routing

Adds a "United Ucard Claim" button (claims/preauth insurance form) that
submits through a full Selenium pipeline mirroring the Tufts SCO claim
worker: frontend handler -> backend route/queue processor -> Python
agent, reusing the persistent login/OTP session from the existing
United Ucard eligibility check. Implements the UHC Dental claim wizard
end-to-end (Provider Information, Patient Information search/select,
Claim Information procedures + questions, Upload Documents, Review and
Sign, Submit); the final confirmation-page PDF/claim-number capture is
still a TODO stub pending that page's DOM.

Also wires United Ucard into the AI chatbot's eligibility flow
(insuranceAliases.json, siteKeyToAutoCheck, clarification options), and
fixes a bug where the AI-column batch claim feature silently defaulted
United Ucard patients to MassHealth because batchColumnDeriveSiteKey
had no matching branch and no job-dispatch case for UNITED_UCARD.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/Backend/src/ai/internal-chat-workflow.ts

@@ -86,6 +86,7 @@ export function siteKeyToAutoCheck(siteKey: string, dob?: string | Date | null):
     case "DELTA_INS":  return "delta-ins";
     case "TUFTS_SCO":  return "tufts-sco";
     case "UNITED_SCO": return "united-sco";
+    case "UNITED_UCARD": return "united-ucard";
     default: {
       // MassHealth: patients under 21 use the CMSP button
       if (dob) {
@@ -428,7 +429,7 @@ async function handleEligibilityById(
         memberId,
         dob: resolvedDob,
         patient,
-        options: ["United SCO / Dental Hub", "Other United (not in app)"],
+        options: ["United SCO / Dental Hub", "United Ucard", "Other United (not in app)"],
       },
     };
   }
@@ -969,7 +970,7 @@ async function handleCheckAndClaim(
         dob: resolvedDob,
         patient,
         procedureNames: c.procedureNames ?? [],
-        options: ["United SCO / Dental Hub", "Other United (not in app)"],
+        options: ["United SCO / Dental Hub", "United Ucard", "Other United (not in app)"],
       },
     };
   }