add Categories management: create CategoriesList component, update admin navbar, and integrate category handling in product forms

client/src/app/app.routes.ts

@@ -8,6 +8,7 @@ import {authOnlyCanActivate, authOnlyCanMatch} from './guards/auth-only.guard';
 import {AdminComponent} from './pages/admin/admin.component';
 import {adminOnlyCanActivate, adminOnlyCanMatch} from './guards/admin-only.guard';
 import {AddProductComponent} from './pages/add-product/add-product.component';
+import {ProductsComponent} from './pages/products/products.component';
 
 export const routes: Routes = [
   {
@@ -48,6 +49,12 @@ export const routes: Routes = [
     canMatch: [adminOnlyCanMatch],
     canActivate: [adminOnlyCanActivate]
   },
+  {
+    path : 'products',
+    component: ProductsComponent,
+    canMatch: [authOnlyCanMatch],
+    canActivate: [authOnlyCanActivate]
+  },
   {
     path : 'add-product',
     component: AddProductComponent,