added invoices and status in cockpit, created info button for contract status types

backend/node_modules/.prisma/client/schema.prisma

@@ -596,12 +596,18 @@ model ContractTaskSubtask {
 
 // ==================== ENERGY CONTRACT DETAILS ====================
 
+enum InvoiceType {
+  INTERIM // Zwischenrechnung
+  FINAL // Schlussrechnung
+  NOT_AVAILABLE // Rechnung nicht mehr zu bekommen
+}
+
 model EnergyContractDetails {
-  id                     Int      @id @default(autoincrement())
-  contractId             Int      @unique
-  contract               Contract @relation(fields: [contractId], references: [id], onDelete: Cascade)
+  id                     Int       @id @default(autoincrement())
+  contractId             Int       @unique
+  contract               Contract  @relation(fields: [contractId], references: [id], onDelete: Cascade)
   meterId                Int?
-  meter                  Meter?   @relation(fields: [meterId], references: [id])
+  meter                  Meter?    @relation(fields: [meterId], references: [id])
   maloId                 String? // Marktlokations-ID
   annualConsumption      Float? // kWh für Strom, m³ für Gas
   annualConsumptionKwh   Float? // kWh für Gas (zusätzlich zu m³)
@@ -610,6 +616,21 @@ model EnergyContractDetails {
   bonus                  Float?
   previousProviderName   String?
   previousCustomerNumber String?
+  invoices               Invoice[] // Rechnungen
+}
+
+model Invoice {
+  id                      Int                   @id @default(autoincrement())
+  energyContractDetailsId Int
+  energyContractDetails   EnergyContractDetails @relation(fields: [energyContractDetailsId], references: [id], onDelete: Cascade)
+  invoiceDate             DateTime
+  invoiceType             InvoiceType
+  documentPath            String? // Pflicht, außer bei NOT_AVAILABLE
+  notes                   String?
+  createdAt               DateTime              @default(now())
+  updatedAt               DateTime              @updatedAt
+
+  @@index([energyContractDetailsId])
 }
 
 // ==================== INTERNET CONTRACT DETAILS ====================