fix: add slug auto-generation fallback for articles without slugs

- Add generateSlug() helper to create URL-friendly slugs from titles
- Apply slug fallback in syncArticles() and syncSingleArticle()
- Handles articles created before slug field was added to schema
- Prevents 'slug cannot be null' database constraint errors

backend/src/modules/strapi.service.ts

@@ -111,6 +111,17 @@ export class StrapiService {
     return {};
   }
 
+  private generateSlug(title: string): string {
+    // Generate slug from title if missing
+    return title
+      .toLowerCase()
+      .trim()
+      .replace(/[^\w\s-]/g, '') // Remove special characters
+      .replace(/\s+/g, '-') // Replace spaces with hyphens
+      .replace(/-+/g, '-') // Replace multiple hyphens with single hyphen
+      .substring(0, 100); // Limit length
+  }
+
   private async findOrCreateCategory(
     categorySlug: string,
   ): Promise<Category | null> {
@@ -241,7 +252,7 @@ export class StrapiService {
           title: strapiArticle.title,
           excerpt: strapiArticle.description,
           content: strapiArticle.content,
-          slug: strapiArticle.slug,
+          slug: strapiArticle.slug || this.generateSlug(strapiArticle.title),
           status: strapiArticle.publishedAt
             ? ArticleStatus.PUBLISHED
             : ArticleStatus.DRAFT,
@@ -328,7 +339,7 @@ export class StrapiService {
         title: strapiArticle.title,
         excerpt: strapiArticle.description,
         content: strapiArticle.content,
-        slug: strapiArticle.slug,
+        slug: strapiArticle.slug || this.generateSlug(strapiArticle.title),
         status,
         tags: [],
         featuredImage: imageUrl,