feat: add Office Contact settings page and reorder Advanced sidebar

- Add OfficeContact Prisma model with receptionist name, dentist name, phone, email, fax fields
- Create GET/PUT /api/office-contact backend route and storage
- Add OfficeContactCard frontend component under Settings > Advanced
- Reorder Advanced sidebar: Office Hours → Office Contact → Twilio Settings → Google AI Settings

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

packages/db/generated/prisma/schema.prisma

@@ -40,6 +40,7 @@ model User {
   twilioSettings       TwilioSettings?
   aiSettings           AiSettings?
   officeHours          OfficeHours?
+  officeContact        OfficeContact?
 }
 
 model Patient {
@@ -580,3 +581,17 @@ model OfficeHours {
 
   @@map("office_hours")
 }
+
+model OfficeContact {
+  id               Int     @id @default(autoincrement())
+  userId           Int     @unique
+  receptionistName String?
+  dentistName      String?
+  phoneNumber      String?
+  email            String?
+  fax              String?
+
+  user User @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  @@map("office_contact")
+}