Refactor helper functions and update seeders

- Simplified `tmpostChannel` and `tmpostDefaultInventory` functions by removing caching logic.
- Changed return type of `namesWithTaxes` method in `CategoryRepository` to `mixed`.
- Enabled `ProductsTableSeeder` and added user association logic for product relations.
- Updated `BrandsSeeder` to include the product ID in the slug.
- Added `old_customer_id` to `options` in `SellersTableSeeder` for user tracking.

app/Helpers/helpers.php

@@ -176,9 +176,7 @@ if (! function_exists('tmpostChannel')) {
      */
     function tmpostChannel(): Channel
     {
-        Cache::rememberForever('tmpostChannel', fn () => Channel::tmpostDefault());
-
-        return Cache::get('tmpostChannel');
+        return Channel::tmpostDefault();
     }
 }
 
@@ -188,9 +186,7 @@ if (! function_exists('tmpostDefaultInventory')) {
      */
     function tmpostDefaultInventory(): mixed
     {
-        Cache::rememberForever('tmpostDefaultInventory', fn () => Inventory::tmpostDefault());
-
-        return Cache::get('tmpostDefaultInventory');
+        return Inventory::tmpostDefault();
     }
 }