借款还款同金额回单须经独立复核确认归属后方可核销（09-17-company-loan-principal-repayment）

- 同一出借人同金额的其他批次曾导出或上传回单（含确认失败后已取消的）时，
  最终核销入口要求已复核的归属确认；OCR 匹配与人工回单复核均不能绕过，
  证据不足保持待对账，本金与占用不变；存在候选时失败回单不能释放占用
- 新表 loan_receipt_attributions（迁移 20261006010000）：绑定交易指纹、
  回单核验与人工录入证据、当时候选集合；依据类型不含时间吻合；复核人须
  当前有资格且独立于登记人、批次创建人、提交人、导出人、回单上传人、
  人工录入人与出借员工；失效记录在重新登记时标为 superseded，历史只增不改
- 借款回单上传取出借人锁，与核销候选检查串行；串行只保证按当时已知候选
  判断，核销之后才出现的新证据留待晚到结果对账流程处理
- 付款就绪检查反映归属要求；页面登记/复核/失效重登，写明同额分期每期需确认
- 测试：两个错误核销复现改为回归断言；证据绑定、确定性并发两种顺序、
  PC 浏览器完整登记复核重登流程；变异测试均变红

注意：借款功能尚不具备真实还款验收条件（失败回单与对账流程、离职后确认
失败、真实回单样本、手机端弹窗、独立复核待完成）；未推送、未部署。

Co-Authored-By: Claude Opus 5.5 <[email protected]>

server/prisma/schema.prisma

@@ -735,6 +735,8 @@ model Employee {
   loan_lender_identities LoanLender[]
   loan_evidence_uploads LoanEvidence[]
 
+  loan_receipt_attributions_proposed LoanReceiptAttribution[] @relation("LoanReceiptAttributionProposer")
+  loan_receipt_attributions_reviewed LoanReceiptAttribution[] @relation("LoanReceiptAttributionReviewer")
   @@map("employees")
 }
 
@@ -1974,6 +1976,7 @@ model PaymentBatch {
   @@index([legal_entity_id], map: "idx_payment_batches_legal_entity")
   @@index([payment_account_id], map: "idx_payment_batches_payment_account")
   @@index([payment_order_last_exported_by], map: "idx_payment_batches_order_exported_by")
+  loan_receipt_attributions LoanReceiptAttribution[]
   @@map("payment_batches")
 }
 
@@ -3979,3 +3982,34 @@ model LoanEvidence {
   @@unique([loan_id, file_sha256, kind])
   @@map("loan_evidences")
 }
+
+// Independently reviewed receipt-to-batch attribution for ambiguous loan
+// repayments (same lender and amount as another exported/receipted batch).
+// Partial unique index (one proposed/approved per batch) and history trigger
+// live in migration 20261006010000_loan_receipt_attribution.
+model LoanReceiptAttribution {
+  id                   String    @id @default(uuid()) @db.Uuid
+  payment_batch_id     String    @db.Uuid
+  fingerprint          String    @db.VarChar(64)
+  key_id               String    @db.VarChar(64)
+  verification_ids     Json
+  manual_proposal_ids  Json
+  competitor_batch_ids Json
+  basis_kind           String    @db.VarChar(32)
+  basis_note           String    @db.VarChar(1000)
+  exclusion_note       String    @db.VarChar(1000)
+  status               String    @default("proposed") @db.VarChar(16)
+  proposed_by          String    @db.Uuid
+  proposed_at          DateTime  @default(now())
+  reviewed_by          String?   @db.Uuid
+  reviewed_at          DateTime?
+  review_note          String?   @db.VarChar(500)
+  superseded_at        DateTime?
+
+  payment_batch PaymentBatch @relation(fields: [payment_batch_id], references: [id], onDelete: Restrict)
+  proposer      Employee     @relation("LoanReceiptAttributionProposer", fields: [proposed_by], references: [id], onDelete: Restrict)
+  reviewer      Employee?    @relation("LoanReceiptAttributionReviewer", fields: [reviewed_by], references: [id], onDelete: Restrict)
+
+  @@index([payment_batch_id, fingerprint], map: "loan_receipt_attributions_batch_fingerprint_idx")
+  @@map("loan_receipt_attributions")
+}