Add smoke tests for UOM conversions and enhance frontend UOM management

- Implemented smoke tests for UOM directionality, ensuring conversions are one-directional and correctly validated.
- Added tests for receiving and selling items in different UOMs, verifying correct quantity handling and error responses.
- Created a UOM conversions panel in the frontend to allow users to manage UOM conversions for items.
- Introduced hooks for allowed UOMs to optimize fetching and caching of UOM data for document line forms.
- Developed utility functions for consistent UOM formatting and conversion handling across the application.

Backend/ERPCore/Controllers/ItemsController.cs

@@ -1,6 +1,7 @@
 using ERPCore.Domain.Enums;
 using ERPCore.Dtos.Common;
 using ERPCore.Dtos.Items;
+using ERPCore.Dtos.Uoms;
 using ERPCore.Services.Interfaces;
 using Microsoft.AspNetCore.Mvc;
 
@@ -11,8 +12,13 @@ namespace ERPCore.Controllers;
 public sealed class ItemsController : ApiControllerBase
 {
     private readonly IItemService _items;
+    private readonly IUomConverter _uomConverter;
 
-    public ItemsController(IItemService items) => _items = items;
+    public ItemsController(IItemService items, IUomConverter uomConverter)
+    {
+        _items = items;
+        _uomConverter = uomConverter;
+    }
 
     /// <summary>List items with optional filters and paging.</summary>
     [HttpGet]
@@ -88,4 +94,15 @@ public sealed class ItemsController : ApiControllerBase
     [ProducesResponseType(StatusCodes.Status404NotFound)]
     public async Task<ActionResult<ItemUomConversionsDto>> UpdateUomConversions(int itemId, [FromBody] UpdateUomConversionsRequest request, CancellationToken ct)
         => Ok(await _items.UpdateUomConversionsAsync(itemId, request, ct));
+
+    /// <summary>
+    /// The UOMs this item may be transacted in — its base UOM plus every UOM it has a
+    /// conversion from, each with the factor to base. Document line forms use this to offer
+    /// only units that will survive posting, instead of the whole global UOM list (FR-MD-02/03).
+    /// </summary>
+    [HttpGet("{itemId:int}/uoms")]
+    [ProducesResponseType(typeof(IReadOnlyList<AllowedUomDto>), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    public async Task<ActionResult<IReadOnlyList<AllowedUomDto>>> GetAllowedUoms(int itemId, CancellationToken ct)
+        => Ok(await _uomConverter.GetAllowedUomsAsync(itemId, ct));
 }