feat(customers): add DTOs for individual and legal customer creation

- Created CreateCustomerIndividualDto for individual customer data with fields: first_name, last_name, national_code, postal_code, is_favorite, and economic_code.
- Created CreateCustomerLegalDto for legal customer data with fields: company_name, economic_code, registration_number, and postal_code.

prisma/schema/sales.prisma

@@ -1,31 +1,38 @@
 model SalesInvoice {
-  id           String   @id @default(uuid())
-  code         String   @unique @db.VarChar(100)
-  total_amount Decimal  @db.Decimal(15, 2)
-  description  String?  @db.Text
-  created_at   DateTime @default(now()) @db.Timestamp(0)
-  updated_at   DateTime @updatedAt @db.Timestamp(0)
-  customer_id  String?
-  account_id   String
-  complex_id   String
+  id               String    @id @default(uuid())
+  code             String    @unique @db.VarChar(100)
+  total_amount     Decimal   @db.Decimal(15, 2)
+  notes            String?   @db.Text
+  unknown_customer Json?     @db.Json
+  invoice_date     DateTime? @default(now()) @db.Timestamp(0)
+  created_at       DateTime  @default(now()) @db.Timestamp(0)
+  updated_at       DateTime  @updatedAt @db.Timestamp(0)
 
-  customer               Customer?             @relation(fields: [customer_id], references: [id])
-  items                  SalesInvoiceItem[]
-  sales_invoice_payments SalesInvoicePayment[]
+  customer_id String?
+  account_id  String
+  complex_id  String
+
+  customer Customer?             @relation(fields: [customer_id], references: [id])
+  items    SalesInvoiceItem[]
+  payments SalesInvoicePayment[]
 
   @@map("sales_invoices")
 }
 
 model SalesInvoiceItem {
-  id           String   @id @default(uuid())
-  quantity     Decimal  @db.Decimal(10, 0)
+  id           String                       @id @default(uuid())
+  quantity     Decimal                      @db.Decimal(10, 0)
   unit_type    UnitType
-  unit_price   Decimal  @default(0.00) @db.Decimal(15, 2)
-  total_amount Decimal  @default(0.00) @db.Decimal(15, 2)
-  created_at   DateTime @default(now()) @db.Timestamp(0)
-  invoice_id   String
-  good_id      String?
-  service_id   String?
+  unit_price   Decimal                      @default(0.00) @db.Decimal(15, 2)
+  total_amount Decimal                      @default(0.00) @db.Decimal(15, 2)
+  created_at   DateTime                     @default(now()) @db.Timestamp(0)
+  discount     Decimal                      @default(0.00) @db.Decimal(15, 2)
+  notes        String?                      @db.Text
+  pricingModel SalesInvoiceItemPricingModel @default(STANDARD)
+
+  invoice_id String
+  good_id    String?
+  service_id String?
 
   payload Json?