fix(blog): auto-generate slug when admin leaves it empty

Allow optional slug on create/update, generate from title with unique fallback,
so BackOffice can publish posts without manual slug entry.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/CMSMicroservice.Application/BlogPostCQ/Commands/UpdateBlogPost/UpdateBlogPostCommandHandler.cs

@@ -1,3 +1,4 @@
+using CMSMicroservice.Application.Common;
 using CMSMicroservice.Application.Common.FileManager;
 using CMSMicroservice.Application.Common.Interfaces;
 using CMSMicroservice.Domain.Entities.Blog;
@@ -29,9 +30,21 @@ public class UpdateBlogPostCommandHandler : IRequestHandler<UpdateBlogPostComman
             ?? throw new KeyNotFoundException($"مقاله با شناسه {request.Id} یافت نشد");
 
         post.Title = request.Title.Trim();
-        // حفظ slug قبلی اگر مقدار جدید خالی باشد
+
         if (!string.IsNullOrWhiteSpace(request.Slug))
-            post.Slug = request.Slug.Trim().ToLower();
+        {
+            post.Slug = await BlogSlugHelper.EnsureUniquePostSlugAsync(
+                _context,
+                BlogSlugHelper.NormalizeOptional(request.Slug)!,
+                post.Id,
+                cancellationToken);
+        }
+        else if (string.IsNullOrWhiteSpace(post.Slug))
+        {
+            var slug = BlogSlugHelper.ResolveForCreate(null, post.Title);
+            post.Slug = await BlogSlugHelper.EnsureUniquePostSlugAsync(
+                _context, slug, post.Id, cancellationToken);
+        }
         post.Summary = request.Summary?.Trim();
         post.HtmlContent = request.HtmlContent;
         post.FeaturedImagePath = request.FeaturedImagePath;