feat: Implement new General Ledger frontend section with comprehensive report screens and cash/bank account management

- Added a new Ledgers sidebar section for statutory-format financial reports and cash/bank-account management.
- Introduced dedicated GL client for API interactions, handling response envelopes and error management.
- Developed report screens for Trial Balance, Balance Sheet, General Ledger, Profit & Loss, Cash Flow, Budget vs Actual, and a new Tax Report.
- Implemented CSV download functionality alongside existing PDF downloads for all report screens.
- Separated Cash and Bank accounts into distinct tables/endpoints, with updated create forms and unified list view.
- Created a new Accounts section for Cheque Management, moving Cash/Bank Accounts from the Ledgers section.
- Updated RBAC navigation to include new permissions and sub-navigation items for the added features.
- Ensured compliance with GL's updated API contract, including renaming fields and adjusting response shapes.
- Addressed various bugs and presentation issues, enhancing user experience across the new module.

Frontend/erp-system/lib/validations/general-ledger.ts

@@ -0,0 +1,55 @@
+// Client-side UX validation only (docs/20-FRONTEND.md §3.1) — required fields the browser
+// already knows about. Everything else is server-authoritative and surfaced via the GL
+// service's own error message (lib/error-map.ts).
+
+export function validateBankAccountForm(input: { accountName: string }): Record<string, string> {
+  const errors: Record<string, string> = {}
+  if (!input.accountName.trim()) errors.accountName = "Account name is required"
+  return errors
+}
+
+export function validateChequeBookForm(input: {
+  branchId: string
+  bankAccountId: string
+  chequeBookNo: string
+  startChequeNo: string
+  endChequeNo: string
+  totalLeaves: string
+  receivedDate: string
+}): Record<string, string> {
+  const errors: Record<string, string> = {}
+  if (!input.branchId.trim()) errors.branchId = "Branch ID is required"
+  if (!input.bankAccountId) errors.bankAccountId = "Select a bank account"
+  if (!input.chequeBookNo.trim()) errors.chequeBookNo = "Cheque book number is required"
+  if (!input.startChequeNo.trim()) errors.startChequeNo = "Start cheque number is required"
+  if (!input.endChequeNo.trim()) errors.endChequeNo = "End cheque number is required"
+  if (!input.totalLeaves.trim()) errors.totalLeaves = "Total leaves is required"
+  if (!input.receivedDate) errors.receivedDate = "Received date is required"
+  return errors
+}
+
+export function validateIssueChequeForm(input: { payeeName: string; issueDate: string; amount: string }): Record<string, string> {
+  const errors: Record<string, string> = {}
+  if (!input.payeeName.trim()) errors.payeeName = "Payee name is required"
+  if (!input.issueDate) errors.issueDate = "Issue date is required"
+  if (!input.amount.trim() || Number(input.amount) <= 0) errors.amount = "Amount must be greater than 0"
+  return errors
+}
+
+export function validateReceivedChequeForm(input: {
+  companyId: string
+  receivedFromName: string
+  chequeNo: string
+  chequeDate: string
+  amount: string
+  receivedDate: string
+}): Record<string, string> {
+  const errors: Record<string, string> = {}
+  if (!input.companyId.trim()) errors.companyId = "Company ID is required"
+  if (!input.receivedFromName.trim()) errors.receivedFromName = "Received-from name is required"
+  if (!input.chequeNo.trim()) errors.chequeNo = "Cheque number is required"
+  if (!input.chequeDate) errors.chequeDate = "Cheque date is required"
+  if (!input.amount.trim() || Number(input.amount) <= 0) errors.amount = "Amount must be greater than 0"
+  if (!input.receivedDate) errors.receivedDate = "Received date is required"
+  return errors
+}