add api category brand and fix product

docs/products-api.md

@@ -55,6 +55,7 @@ Query params:
 - `attributes` as JSON string
 - `tags` as JSON string array
 - `featured`
+- `sort`: `newest | oldest | price_asc | price_desc | popular | top_rated`
 - `page`
 - `limit`
 
@@ -65,12 +66,76 @@ Optional request header:
 Example:
 
 ```http
-GET /api/products?search=skf&featured=true&page=1&limit=20
+GET /api/products?search=skf&featured=true&sort=price_asc&page=1&limit=20
 x-product-type: Industrial
 ```
 
 List response items are intentionally lightweight and include only fields needed for product cards / list pages. The `attributes` array is limited to the first 2 visible attributes, sorted by `displayOrder`.
 
+### `GET /api/products/brands/:brandSlug`
+
+Lists published products for one brand by brand slug.
+
+Supports the same query params as `GET /api/products`:
+
+- `search`
+- `featured`
+- `sort`
+- `page`
+- `limit`
+
+Optional request header:
+
+- `x-product-type`: `Industrial | Automotive`
+
+### `GET /api/products/brands/:brandSlug/filters`
+
+Returns available brand page filters relative to the selected brand and current query filters.
+
+Response shape:
+
+- `categories`: available categories with count
+- `attributes`: available filterable attributes and their values with count
+- `stock`: `inStock` and `outOfStock`
+
+Optional request header:
+
+- `x-product-type`: `Industrial | Automotive`
+
+### `GET /api/products/categories/:categorySlug`
+
+Lists published products for one category by category slug.
+
+Supports the same query params as `GET /api/products`:
+
+- `search`
+- `featured`
+- `sort`
+- `page`
+- `limit`
+
+Optional request header:
+
+- `x-product-type`: `Industrial | Automotive`
+
+### `GET /api/products/categories/:categorySlug/filters`
+
+Returns available category page filters relative to the selected category and current query filters.
+
+Response shape:
+
+- `brands`: available brands with count
+- `attributes`: available filterable attributes and their values with count
+- `stock`: `inStock` and `outOfStock`
+
+Optional request header:
+
+- `x-product-type`: `Industrial | Automotive`
+
+### `GET /api/product/:slug`
+
+Returns one published product by slug with category and up to 10 approved reviews.
+
 ### `GET /api/products/:id`
 
 Returns one published product with category and up to 10 approved reviews.
@@ -117,6 +182,7 @@ Query params:
 - `attributes` as JSON string
 - `tags` as JSON string array
 - `featured`
+- `sort`: `newest | oldest | price_asc | price_desc | popular | top_rated`
 - `page`
 - `limit`