feat(efectivo): the EFE cash receipt book, folio and posting in one step

The office still issues cash receipts from Access (EFE MENU -> EFE). This is
that form: cliente, fecha, monto + moneda, concepto, elaboró (the logged-in
user), fecha de depósito, and a folio that continues the legacy book.

- cash_receipts, folio unique. Next folio = one past the highest of the
  platform's receipts and the imported utilities EFECTIVO journal, so after
  the cutover import it lands on the office's next number (13935 on prod
  today). A typed folio the legacy book already used is refused.
- Issuing a receipt posts its credit in the same database transaction, as
  legacy posted to DATOS2: reference C<folio>, CASH DEPOSIT, pseudo check
  CASH<MMDD><P|D>. Dollars with a rate credit a pesos ledger (1,500 USD at
  16.80 -> 25,200 MXN, as C13830 did). Voiding that row voids the receipt.
- /efectivo: issue, search, record the deposit date; /efectivo/<folio>
  prints the receipt.
- Reporte de efectivo now lists platform receipts by receipt, not by check,
  so each is counted once.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/database/prisma/schema.prisma

@@ -131,6 +131,7 @@ model Customer {
 
   statementDocuments StatementDocument[]
   statementSplits    StatementDocumentSplit[]
+  cashReceipts       CashReceipt[]
   policyOcrDocuments PolicyOcrDocument[]      @relation("PolicyOcrDocumentCustomer")
 
   emailNotificationLogs EmailNotificationLog[]
@@ -884,6 +885,7 @@ model Transaction {
   /// Set only on OCR-posted rows — the statement page this came from.
   statementDocument StatementDocument?
   statementSplit    StatementDocumentSplit? @relation("StatementDocumentSplitTransaction")
+  cashReceipt       CashReceipt?
   policyOcrDocument PolicyOcrDocument?      @relation("PolicyOcrDocumentTransaction")
 
   @@unique([legacySourceDb, legacySourceTable, legacyId])
@@ -1005,6 +1007,7 @@ model User {
 
   statementBatches   StatementBatch[]    @relation("StatementBatchUploader")
   statementsReviewed StatementDocument[] @relation("StatementDocumentReviewer")
+  cashReceipts       CashReceipt[]       @relation("CashReceiptPreparer")
 
   policyOcrBatches  PolicyOcrBatch[]    @relation("PolicyOcrBatchUploader")
   policyOcrReviewed PolicyOcrDocument[] @relation("PolicyOcrDocumentReviewer")
@@ -1287,3 +1290,35 @@ model AppSetting {
 
   @@map("app_settings")
 }
+
+/// The EFE cash receipt book (legacy EFE form / EFECTIVO table): the paper the
+/// office hands a customer who pays in cash. A journal, not a ledger — the
+/// money reaches the customer's balance through `transaction`, posted with it
+/// as `C<folio>` exactly as legacy posted to DATOS2. Voiding that row voids
+/// the receipt.
+model CashReceipt {
+  id            String      @id @default(uuid())
+  /// Printed receipt number. Continues the legacy book's sequence.
+  folio         Int         @unique
+  customerId    String
+  customer      Customer    @relation(fields: [customerId], references: [id])
+  receivedAt    DateTime
+  amount        Decimal     @db.Decimal(12, 2)
+  currency      Currency
+  /// Set when dollars are credited to a pesos ledger, as legacy did; the
+  /// posted row then carries amount × rate in MXN.
+  exchangeRate  Decimal?    @db.Decimal(10, 4)
+  concept       String      @db.Text
+  /// ELABORÓ — whoever was logged in.
+  preparedById  String
+  preparedBy    User        @relation("CashReceiptPreparer", fields: [preparedById], references: [id])
+  /// FECHA DEPÓSITO — filled in when the cash reaches the bank.
+  depositedAt   DateTime?
+  transactionId String      @unique
+  transaction   Transaction @relation(fields: [transactionId], references: [id])
+  createdAt     DateTime    @default(now())
+
+  @@index([customerId])
+  @@index([receivedAt])
+  @@map("cash_receipts")
+}