Add product catalog with per-store section memory

Introduces a global Products catalog plus per-family overrides and
private FamilyProducts, exposed via /api/products with a merged
search. Shopping list items and recipe ingredients gain optional
ProductId/FamilyProductId links, and a new ProductStoreSection
table remembers which section a product was last placed in at a
given store so future adds auto-assign the right section.

Frontend gets a reusable ProductTypeahead component, wired into
list-item add and recipe ingredient entry with free-form fallback.

A startup CatalogSeeder loads ~115 curated staples from an embedded
JSON resource via INSERT ... ON CONFLICT DO NOTHING; skipped under
the Testing environment so integration tests keep a clean slate.

src/backend/YesChef.Api/Features/Recipes/RecipeEndpoints.cs

@@ -2,12 +2,13 @@ using Microsoft.EntityFrameworkCore;
 using YesChef.Api.Auth;
 using YesChef.Api.Data;
 using YesChef.Api.Entities;
+using YesChef.Api.Features.ShoppingLists;
 
 namespace YesChef.Api.Features.Recipes;
 
 public static class RecipeEndpoints
 {
-    public record IngredientRequest(string Name, string? Quantity, int SortOrder);
+    public record IngredientRequest(string Name, string? Quantity, int SortOrder, int? ProductId = null, int? FamilyProductId = null);
     public record CreateRecipeRequest(string Title, string? Description, string? Instructions, int? Servings, string? SourceUrl, List<IngredientRequest> Ingredients);
     public record UpdateRecipeRequest(string Title, string? Description, string? Instructions, int? Servings, string? SourceUrl, List<IngredientRequest> Ingredients);
 
@@ -36,6 +37,13 @@ public static class RecipeEndpoints
         group.MapPost("/", async (CreateRecipeRequest request, YesChefDb db, HttpContext http) =>
         {
             var familyId = http.User.GetFamilyId();
+
+            foreach (var ing in request.Ingredients)
+            {
+                if (await ShoppingListEndpoints.ValidateProductLink(db, familyId, ing.ProductId, ing.FamilyProductId) is { } error)
+                    return error;
+            }
+
             var recipe = new Recipe
             {
                 FamilyId = familyId,
@@ -50,7 +58,9 @@ public static class RecipeEndpoints
                     FamilyId = familyId,
                     Name = i.Name,
                     Quantity = i.Quantity,
-                    SortOrder = i.SortOrder
+                    SortOrder = i.SortOrder,
+                    ProductId = i.ProductId,
+                    FamilyProductId = i.FamilyProductId
                 }).ToList()
             };
 
@@ -80,7 +90,7 @@ public static class RecipeEndpoints
                 recipe.SourceUrl,
                 CreatedBy = recipe.CreatedByUser.Name,
                 recipe.UpdatedAt,
-                Ingredients = recipe.Ingredients.Select(i => new { i.Id, i.Name, i.Quantity, i.SortOrder })
+                Ingredients = recipe.Ingredients.Select(i => new { i.Id, i.Name, i.Quantity, i.SortOrder, i.ProductId, i.FamilyProductId })
             });
         });
 
@@ -93,6 +103,12 @@ public static class RecipeEndpoints
                 .FirstOrDefaultAsync();
             if (recipe is null) return Results.NotFound();
 
+            foreach (var ing in request.Ingredients)
+            {
+                if (await ShoppingListEndpoints.ValidateProductLink(db, familyId, ing.ProductId, ing.FamilyProductId) is { } error)
+                    return error;
+            }
+
             recipe.Title = request.Title;
             recipe.Description = request.Description;
             recipe.Instructions = request.Instructions;
@@ -106,7 +122,9 @@ public static class RecipeEndpoints
                 FamilyId = familyId,
                 Name = i.Name,
                 Quantity = i.Quantity,
-                SortOrder = i.SortOrder
+                SortOrder = i.SortOrder,
+                ProductId = i.ProductId,
+                FamilyProductId = i.FamilyProductId
             }).ToList();
 
             await db.SaveChangesAsync();