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.

Backend/ERPCore/Services/GeneralLedgerService.cs

@@ -0,0 +1,16 @@
+using ERPCore.Infra.Gl;
+using ERPCore.Services.Interfaces;
+
+namespace ERPCore.Services;
+
+/// <inheritdoc cref="IGeneralLedgerService"/>
+public sealed class GeneralLedgerService : IGeneralLedgerService
+{
+    private readonly IGeneralLedgerClient _client;
+
+    public GeneralLedgerService(IGeneralLedgerClient client) => _client = client;
+
+    public Task<GeneralLedgerResponse> ForwardAsync(
+        HttpMethod method, string path, string? queryString, string? contentType, Stream? body, CancellationToken ct)
+        => _client.SendAsync(method, path, queryString, contentType, body, ct);
+}

Backend/ERPCore/Services/Interfaces/IGeneralLedgerService.cs

@@ -0,0 +1,16 @@
+using ERPCore.Infra.Gl;
+
+namespace ERPCore.Services.Interfaces;
+
+/// <summary>
+/// Single entry point into the external General Ledger service — the one function
+/// used both by <see cref="ERPCore.Controllers.GeneralLedgerController"/> (frontend
+/// requests, forwarded verbatim) and, once wired, other ERPCore services that need to
+/// post directly to GL (e.g. GRN confirm, adjustments — docs/12-GENERAL-LEDGER-INTEGRATION.md).
+/// No business logic lives here yet; this pass only connects the transport.
+/// </summary>
+public interface IGeneralLedgerService
+{
+    Task<GeneralLedgerResponse> ForwardAsync(
+        HttpMethod method, string path, string? queryString, string? contentType, Stream? body, CancellationToken ct);
+}