Add IsIncoming inventory flag and catalog-to-incoming powder flow in item wizard

- InventoryItem.IsIncoming: marks powder ordered but not yet received; enables QR code
  printing on work orders while the shipment is in transit
- InventoryController.CreateIncomingFromCatalog: POST endpoint creates a 0-balance inventory
  record from a PowderCatalogItem and returns it in wizard-compatible shape
- item-wizard.js: custom coat tab now searches the platform powder catalog as a fallback;
  catalog results show an 'Add as Incoming Order' option; createIncomingFromCatalog POSTs
  to server and selects the new item without a page refresh
- QuoteItemCoatDto: CatalogItemId + AddAsIncoming fields so the wizard can signal server-side
  incoming-item creation during quote save
- Inventory Create/Edit/Index views: IsIncoming badge and field
- IInventoryAiLookupService: minor interface update
- Migration: AddInventoryIsIncoming

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Application/Interfaces/IInventoryAiLookupService.cs

@@ -47,8 +47,10 @@ public interface IInventoryAiLookupService
     /// <summary>
     /// Fetch cure specs, color families, finish, and clear-coat data from a known product URL.
     /// Skips the Serper search step; used after a catalog hit to augment catalog fields.
+    /// When <paramref name="tdsFallbackUrl"/> is supplied and cure specs are still null after
+    /// the main fetch, the TDS page is tried automatically before returning.
     /// </summary>
-    Task<InventoryAiLookupResult> LookupByUrlAsync(string url, string? colorName);
+    Task<InventoryAiLookupResult> LookupByUrlAsync(string url, string? colorName, string? tdsFallbackUrl = null);
 
     /// <summary>
     /// Read a powder label photo and extract manufacturer, color name, SKU, and cure specs