backfill from projects

server/prisma/schema.prisma

@@ -618,6 +618,7 @@ model Project {
   shipment      Shipment? @relation(fields: [shipmentId], references: [id], onDelete: SetNull)
   owner         User? @relation("ProjectOwner", fields: [ownerId], references: [id], onDelete: SetNull)
   workOrders    WorkOrder[]
+  purchaseOrders PurchaseOrder[]
   milestones    ProjectMilestone[]
 
   @@index([customerId, createdAt])
@@ -864,6 +865,7 @@ model PurchaseOrder {
   id             String   @id @default(cuid())
   documentNumber String   @unique
   vendorId       String
+  projectId      String?
   status         String
   issueDate      DateTime
   taxPercent     Float    @default(0)
@@ -872,10 +874,13 @@ model PurchaseOrder {
   createdAt      DateTime @default(now())
   updatedAt      DateTime @updatedAt
   vendor         Vendor   @relation(fields: [vendorId], references: [id], onDelete: Restrict)
+  project        Project? @relation(fields: [projectId], references: [id], onDelete: SetNull)
   lines          PurchaseOrderLine[]
   receipts       PurchaseReceipt[]
   revisions      PurchaseOrderRevision[]
   capexEntries   CapexEntry[]
+
+  @@index([projectId, issueDate])
 }
 
 model PurchaseOrderLine {