исправил клиент, пути в функциях, добавил переменную окружения

src/features/catalog/categoriesSlice.ts

@@ -1,11 +1,11 @@
 import { createSlice, createAsyncThunk } from "@reduxjs/toolkit";
 import type { Category } from "../../types/categories";
-import axios from "axios";
+import {client} from "../../api/client";
 
 export const fetchCategories = createAsyncThunk<Category[]>(
   "categories/fetchCategories",
   async () => {
-    const res = await axios.get<Category[]>("/api/categories");
+    const res = await client.get<Category[]>("/categories");
     return res.data;
   }
 );

src/features/catalog/productsSlice.ts

@@ -1,6 +1,6 @@
 import { createAsyncThunk, createSlice } from "@reduxjs/toolkit";
 import type {PayloadAction} from "@reduxjs/toolkit";
-import client from "../../api/client";
+import {client} from "../../api/client";
 import type { Product } from "../../types/product";
 import axios from "axios";
 
@@ -42,7 +42,7 @@ export const fetchProductsByCategory = createAsyncThunk(
 export const fetchProductById = createAsyncThunk(
   "product/fetchById",
   async (id: string) => {
-    const response = await axios.get(`/api/products/${id}`);
+    const response = await client.get<Product>(`/products/${id}`);
     return response.data;
   }
 );