fix(search): correction recherche fuzzy catégories

- Backend : seuil word_similarity >= 0.4 (au lieu de > 0.4) sur cat.name
- Frontend : correction erreur TypeScript dans CategoryService.list()
  (params typé Record<string,string> pour satisfaire Angular HttpClient)
  — le code précédent ne compilait pas, la recherche était ignorée

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Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

front-public/src/app/core/category.service.ts

@@ -12,8 +12,10 @@ export class CategoryService {
   private http = inject(HttpClient);
   private baseUrl = '/api/categories';
 
-  list(): Observable<CategoryListResponse> {
-    return this.http.get<CategoryListResponse>(this.baseUrl);
+  list(search?: string): Observable<CategoryListResponse> {
+    const params: Record<string, string> = {};
+    if (search?.trim()) params['search'] = search;
+    return this.http.get<CategoryListResponse>(this.baseUrl, { params });
   }
 
   browse(id: string | null): Observable<CategoryBrowseResponse> {