feat(03-03): Ticket schema, categories, migration, and tenant scoping

- Added TicketStatus, TicketPriority, TicketSource enums to schema
- Added TicketCategory model (tenant-scoped, unique per tenant by name)
- Added Ticket model with lifecycle fields (status, priority, source, resolvedAt, closedAt)
- Added reverse relations: Subscriber.tickets, User.createdTickets, TicketCategory.tickets
- Applied migration 20260304233528_add_tickets
- Added ticket and ticketCategory to TENANT_SCOPED_MODELS with full extension blocks
- Seeded 6 default ISP ticket categories in createTenant transaction

prisma/schema.prisma

@@ -100,6 +100,25 @@ enum PaymentStatus {
   VOIDED
 }
 
+enum TicketStatus {
+  OPEN
+  ASSIGNED
+  RESOLVED
+  CLOSED
+}
+
+enum TicketPriority {
+  LOW
+  MEDIUM
+  HIGH
+  URGENT
+}
+
+enum TicketSource {
+  STAFF
+  SUBSCRIBER
+}
+
 // =============================================================================
 // MODELS
 // =============================================================================
@@ -258,6 +277,7 @@ model Subscriber {
 
   invoices      Invoice[]
   payments      Payment[]
+  tickets       Ticket[]
 
   /// Account numbers must be unique within a tenant
   @@unique([tenantId, accountNumber])
@@ -340,6 +360,8 @@ model User {
   recordedPayments Payment[] @relation("PaymentRecordedBy")
   /// Zone assignments for collector role (which zones this user can collect from)
   zoneAssignments ZoneAssignment[]
+  /// Tickets this user created (staff or subscriber portal)
+  createdTickets  Ticket[]         @relation("TicketCreatedBy")
 
   createdAt DateTime @default(now())
   updatedAt DateTime @updatedAt
@@ -529,6 +551,63 @@ model PaymentAllocation {
   @@index([tenantId])
 }
 
+/// A TicketCategory is an admin-configurable label for classifying support tickets.
+/// Default ISP categories are seeded at tenant creation.
+/// Deactivated categories (isActive=false) cannot be used for new tickets.
+model TicketCategory {
+  id          String   @id @default(uuid())
+  tenantId    String
+  name        String
+  description String?
+  isActive    Boolean  @default(true)
+  createdAt   DateTime @default(now())
+  updatedAt   DateTime @updatedAt
+
+  tickets     Ticket[]
+
+  /// Category names must be unique within a tenant
+  @@unique([tenantId, name])
+  /// RLS-ready index — always present on tenant-scoped models
+  @@index([tenantId])
+}
+
+/// A Ticket records a support request from a subscriber or staff member.
+/// Tickets follow the lifecycle: OPEN -> ASSIGNED -> RESOLVED -> CLOSED.
+/// Status transitions are validated by the ticket service guard map.
+model Ticket {
+  id           String         @id @default(uuid())
+  tenantId     String
+  /// Auto-generated sequential identifier per tenant (e.g., "TKT-0001")
+  ticketNumber String
+  subject      String
+  description  String
+  categoryId   String
+  category     TicketCategory @relation(fields: [categoryId], references: [id])
+  priority     TicketPriority @default(MEDIUM)
+  status       TicketStatus   @default(OPEN)
+  source       TicketSource   @default(STAFF)
+  /// The subscriber this ticket is about (optional — not all tickets are subscriber-specific)
+  subscriberId String?
+  subscriber   Subscriber?    @relation(fields: [subscriberId], references: [id])
+  /// The staff member or subscriber who created this ticket
+  createdById  String
+  createdBy    User           @relation("TicketCreatedBy", fields: [createdById], references: [id])
+  resolvedAt   DateTime?
+  closedAt     DateTime?
+  /// Internal staff notes
+  notes        String?
+  createdAt    DateTime       @default(now())
+  updatedAt    DateTime       @updatedAt
+
+  /// Ticket numbers must be unique within a tenant
+  @@unique([tenantId, ticketNumber])
+  /// RLS-ready index — always present on tenant-scoped models
+  @@index([tenantId])
+  @@index([tenantId, status])
+  @@index([tenantId, categoryId])
+  @@index([subscriberId])
+}
+
 /// A single line item on an Invoice (e.g., "50 Mbps Monthly Service — $49.99").
 model InvoiceLine {
   id          String   @id @default(uuid())