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>

packages/db/generated/prisma/schema.prisma

@@ -51,6 +51,7 @@ model User {
   insuranceContacts    InsuranceContact[]
   patientConversations PatientConversation[]
   labRxTemplates       LabRxTemplate[]
+  seleniumSettings     SeleniumSettings?
 }
 
 model Patient {
@@ -707,7 +708,6 @@ model LabRxTemplate {
   caseType     String?
   material     String?
   instructions String?
-  doctorName   String?
   sortOrder    Int      @default(0)
   createdAt    DateTime @default(now())
   updatedAt    DateTime @updatedAt
@@ -745,3 +745,13 @@ model CommissionBatchItem {
   @@unique([commissionBatchId, paymentId])
   @@index([paymentId])
 }
+
+model SeleniumSettings {
+  id             Int    @id @default(autoincrement())
+  userId         Int    @unique
+  paymentGroupId String @default("")
+
+  user User @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  @@map("selenium_settings")
+}