Phase 3: Bank reconciliation system

Added complete bank statement reconciliation workflow:

Database Schema:
- BankStatement: metadata for uploaded statements
- BankStatementLine: individual transactions from statements
- BankReconciliation: links system transactions to bank lines

Features:
- CSV import with flexible format detection (DD/MM/YYYY, YYYY-MM-DD dates)
- Auto-matching algorithm: exact amount+date = 100% confidence, fuzzy matching up to 7 days
- Manual matching UI for unmatched transactions
- Discrepancy detection (amount mismatches)
- Reconciliation dashboard with summary stats
- Statement history view with status tracking

Pages:
- /admin/accounts/reconciliation: Dashboard and statement list
- /admin/accounts/reconciliation?id=X: Statement detail with matching UI
- /admin/accounts/reconciliation/upload: CSV upload form

Server Actions:
- uploadBankStatement: CSV parsing and auto-matching
- manualMatch: User-initiated transaction linking
- unmatchBankLine: Remove incorrect match
- archiveStatement: Mark statement as complete
- markReconciled: Finalize reconciliation

Utils:
- parseCSV: Flexible bank statement parser
- autoMatchTransactions: Fuzzy matching algorithm
- getReconciliationSummary: Stats calculation

UI Components:
- ReconciliationClient: Interactive matching interface with tabs
- Manual match form: User-friendly transaction linking

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

prisma/schema.prisma

@@ -417,3 +417,58 @@ model FinancialAuditLog {
   changedBy   String?  // "SYSTEM" or IP address if admin
   reason      String?  // why was this changed
 }
+
+// Bank statement uploaded for reconciliation
+model BankStatement {
+  id              String                @id @default(cuid())
+  filename        String                // original filename
+  bankName        String?               // e.g., "HSBC", "Barclays"
+  accountNumber   String?               // last 4 digits for safety
+  statementMonth  DateTime              // the month this statement covers
+  startDate       DateTime              // first transaction date in statement
+  endDate         DateTime              // last transaction date in statement
+  totalTransactions Int                 // count of lines in statement
+  totalAmount     Int?                  // cents, total of all transactions (for verification)
+  status          String    @default("PENDING") // PENDING, IN_PROGRESS, RECONCILED, ARCHIVED
+  uploadedAt      DateTime  @default(now())
+  reconciliedAt   DateTime? // when reconciliation was completed
+  lines           BankStatementLine[]
+  reconciliations BankReconciliation[]
+}
+
+// Individual transaction line from a bank statement
+model BankStatementLine {
+  id              String   @id @default(cuid())
+  statementId     String
+  statement       BankStatement @relation(fields: [statementId], references: [id], onDelete: Cascade)
+  date            DateTime  // transaction date
+  description     String    // e.g., "STRIPE DEPOSIT", "TRANSFER TO SAVINGS"
+  amount          Int       // cents, positive for credit, negative for debit
+  balance         Int?      // account balance after this transaction (if provided)
+  reference       String?   // transaction reference from bank
+  matched         Boolean   @default(false) // whether this line has been reconciled
+  reconciliation  BankReconciliation? // the matched transaction, if any
+  createdAt       DateTime  @default(now())
+}
+
+// Link between system transaction (order/sale/expense) and bank statement line
+model BankReconciliation {
+  id                  String   @id @default(cuid())
+  statementId         String
+  statement           BankStatement @relation(fields: [statementId], references: [id], onDelete: Cascade)
+  bankLineId          String   @unique
+  bankLine            BankStatementLine @relation(fields: [bankLineId], references: [id], onDelete: Cascade)
+
+  // Which system transaction this was matched to
+  transactionType     String   // "ORDER", "MANUAL_SALE", "REFUND", "EXPENSE", "TRANSFER_OUT", "FEE", "OTHER"
+  transactionId       String?  // ID of the order/sale/expense if applicable
+  description         String   // what the match was (e.g., "Order #12345", "Stripe fee")
+  systemAmount        Int      // cents, amount in our system
+  bankAmount          Int      // cents, amount on bank statement
+  amountMatches       Boolean  // whether system and bank amounts are equal
+
+  matchedAt           DateTime @default(now())
+  matchedBy           String?  // IP/admin who manually matched this (null if auto-matched)
+  confidence          Int      @default(100) // 0-100, how confident the match is (100=exact amount+date, <100=fuzzy match)
+  notes               String?  // manual notes about the match
+}