feat: add Lab RX feature with template management and auto-seed defaults

- New lab_rx_template table with sortOrder and Prisma migrations
- Backend CRUD + reorder routes at /api/lab-rx/templates
- Auto-seeds 3 Highland Dental Studio defaults on first use per user
- LabRxModal: template picker, inline rename, up/down reorder, full
  template form with sections (Template Name / Lab Info / Case Details)
- RX popup: Tooth Number, Shade, Due Date, Doctor (from NPI providers),
  Instructions pre-filled with "Please make / Thank you!", print output
- lab-rx-templates.ts config file for future git-managed additions

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

packages/db/generated/prisma/schema.prisma

@@ -50,6 +50,7 @@ model User {
   procedureTimeslot    ProcedureTimeslot?
   insuranceContacts    InsuranceContact[]
   patientConversations PatientConversation[]
+  labRxTemplates       LabRxTemplate[]
 }
 
 model Patient {
@@ -694,6 +695,29 @@ model PatientConversation {
   @@map("patient_conversation")
 }
 
+model LabRxTemplate {
+  id           Int      @id @default(autoincrement())
+  userId       Int
+  name         String
+  labName      String?
+  labPhone     String?
+  labFax       String?
+  labAddress   String?
+  labAccount   String?
+  caseType     String?
+  material     String?
+  instructions String?
+  doctorName   String?
+  sortOrder    Int      @default(0)
+  createdAt    DateTime @default(now())
+  updatedAt    DateTime @updatedAt
+
+  user User @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  @@index([userId])
+  @@map("lab_rx_template")
+}
+
 // Commission tracking
 model CommissionBatch {
   id               Int      @id @default(autoincrement())