Fix category lookup - handle French characters and existing categories better

### Fixes:
- Improved get_or_create_category() with multiple lookup strategies
- Handle French characters in category names (Jeu vidéo, Téléchargement)
- Better handling of 'term_exists' 400 error from WordPress
- Fetch existing category details when creation fails

### Lookup Order:
1. Exact name match (case-insensitive)
2. Slug match
3. Normalized slug (handles French characters)
4. Partial name match

### Benefits:
- No more errors for existing categories
- Handles accented characters properly
- Better caching of existing categories
- More robust category creation

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

src/seo/category_manager.py

@@ -132,12 +132,33 @@ class WordPressCategoryManager:
                     }
                 
                 return category_data['id']
-            elif response.status_code == 409:
-                # Category already exists
-                logger.info(f"  Category '{category_name}' already exists")
-                existing = response.json()
-                if isinstance(existing, list) and len(existing) > 0:
-                    return existing[0]['id']
+            elif response.status_code == 400:
+                # Category might already exist - search for it
+                error_data = response.json()
+                if error_data.get('code') == 'term_exists':
+                    term_id = error_data.get('data', {}).get('term_id')
+                    if term_id:
+                        logger.info(f"  Category '{category_name}' already exists (ID: {term_id})")
+                        
+                        # Fetch the category details
+                        cat_response = requests.get(
+                            f"{base_url}/wp-json/wp/v2/categories/{term_id}",
+                            auth=auth,
+                            timeout=10
+                        )
+                        if cat_response.status_code == 200:
+                            cat_data = cat_response.json()
+                            # Update cache
+                            if site_name in self.category_cache:
+                                self.category_cache[site_name][cat_data['slug']] = {
+                                    'id': cat_data['id'],
+                                    'name': cat_data['name'],
+                                    'slug': cat_data['slug'],
+                                    'count': cat_data.get('count', 0)
+                                }
+                            return cat_data['id']
+                
+                logger.warning(f"  Category already exists or error: {error_data}")
                 return None
             else:
                 logger.error(f"Error creating category: {response.status_code} - {response.text}")
@@ -164,21 +185,42 @@ class WordPressCategoryManager:
         if site_name not in self.category_cache:
             self.fetch_categories(site_name)
         
-        # Check if category exists
-        slug = category_name.lower().replace(' ', '-').replace('/', '-')
+        # Check if category exists (by exact name first)
         categories = self.category_cache.get(site_name, {})
         
+        # Try exact name match (case-insensitive)
+        category_name_lower = category_name.lower()
+        for slug, cat_data in categories.items():
+            if cat_data['name'].lower() == category_name_lower:
+                logger.info(f"✓ Found existing category '{category_name}' (ID: {cat_data['id']})")
+                return cat_data['id']
+        
+        # Try slug match
+        slug = category_name.lower().replace(' ', '-').replace('/', '-')
         if slug in categories:
             logger.info(f"✓ Found existing category '{category_name}' (ID: {categories[slug]['id']})")
             return categories[slug]['id']
         
-        # Try alternative slug formats
-        alt_slug = category_name.lower().replace(' ', '-')
-        if alt_slug in categories:
-            logger.info(f"✓ Found existing category '{category_name}' (ID: {categories[alt_slug]['id']})")
-            return categories[alt_slug]['id']
+        # Try alternative slug formats (handle French characters)
+        import unicodedata
+        normalized_slug = unicodedata.normalize('NFKD', slug)\
+            .encode('ascii', 'ignore')\
+            .decode('ascii')\
+            .lower()\
+            .replace(' ', '-')
+        
+        if normalized_slug in categories:
+            logger.info(f"✓ Found existing category '{category_name}' (ID: {categories[normalized_slug]['id']})")
+            return categories[normalized_slug]['id']
+        
+        # Try partial match (if slug contains the category name)
+        for slug, cat_data in categories.items():
+            if category_name_lower in cat_data['name'].lower() or cat_data['name'].lower() in category_name_lower:
+                logger.info(f"✓ Found similar category '{cat_data['name']}' (ID: {cat_data['id']})")
+                return cat_data['id']
         
         # Create new category
+        logger.info(f"Creating new category '{category_name}'...")
         return self.create_category(site_name, category_name, description)
 
     def assign_post_to_category(self, site_name: str, post_id: int,