fix(01): align image upload field name and wrap category delete in transaction

src/client/lib/api.ts

@@ -52,7 +52,7 @@ export async function apiDelete<T>(url: string): Promise<T> {
 
 export async function apiUpload<T>(url: string, file: File): Promise<T> {
   const formData = new FormData();
-  formData.append("file", file);
+  formData.append("image", file);
   const res = await fetch(url, {
     method: "POST",
     body: formData,

src/server/services/category.service.ts

@@ -63,14 +63,15 @@ export function deleteCategory(
     return { success: false, error: "Category not found" };
   }
 
-  // Reassign items to Uncategorized (id=1), then delete
+  // Reassign items to Uncategorized (id=1), then delete atomically
-  // Use a transaction for atomicity
+  db.transaction(() => {
     db.update(items)
       .set({ categoryId: 1 })
       .where(eq(items.categoryId, id))
       .run();
 
     db.delete(categories).where(eq(categories.id, id)).run();
+  });
 
   return { success: true };
 }