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/Controllers/GeneralLedgerController.cs

@@ -0,0 +1,43 @@
+using ERPCore.Services.Interfaces;
+using Microsoft.AspNetCore.Mvc;
+
+namespace ERPCore.Controllers;
+
+/// <summary>
+/// Generic reverse proxy into the external General Ledger service — forwards every
+/// method/path/query/body under this prefix verbatim via
+/// <see cref="IGeneralLedgerService"/> and returns GL's response (status, content-type,
+/// body) unchanged. No endpoint-specific shape lives here; see
+/// docs/12-GENERAL-LEDGER-INTEGRATION.md for the full GL contract and what this proxy
+/// does and doesn't do. Gated by the same ERP door policy as every other v1 endpoint
+/// (<see cref="ApiControllerBase"/>) — the shared GL API key is attached server-side
+/// only and is never exposed to the frontend.
+/// </summary>
+[Route("api/v1/gl")]
+public sealed class GeneralLedgerController : ApiControllerBase
+{
+    private readonly IGeneralLedgerService _gl;
+
+    public GeneralLedgerController(IGeneralLedgerService gl) => _gl = gl;
+
+    [HttpGet("{**path}")]
+    public Task<IActionResult> Get(string path, CancellationToken ct) => ForwardAsync(HttpMethod.Get, path, ct);
+
+    [HttpPost("{**path}")]
+    public Task<IActionResult> Post(string path, CancellationToken ct) => ForwardAsync(HttpMethod.Post, path, ct);
+
+    [HttpPut("{**path}")]
+    public Task<IActionResult> Put(string path, CancellationToken ct) => ForwardAsync(HttpMethod.Put, path, ct);
+
+    private async Task<IActionResult> ForwardAsync(HttpMethod method, string path, CancellationToken ct)
+    {
+        var body = method == HttpMethod.Get ? null : Request.Body;
+        var result = await _gl.ForwardAsync(method, path, Request.QueryString.Value, Request.ContentType, body, ct);
+        return new ContentResult
+        {
+            StatusCode = result.StatusCode,
+            Content = result.Body,
+            ContentType = result.ContentType ?? "application/json"
+        };
+    }
+}