ver. 0.302: REST API product variants, attributes dictionary, attribute filtering

- Add variant CRUD endpoints (variants, create_variant, update_variant, delete_variant)
- Add dictionaries/attributes endpoint with multilingual names and values
- Add attribute_* filter params for product list filtering by attribute values
- Enrich product detail attributes with translated names (attribute_names, value_names)
- Include variants array in product detail response for parent products
- Add price_brutto validation on product create
- Batch-load attribute/value translations (4 queries instead of N+1)
- Add 43 new unit tests (730 total, 2066 assertions)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

updates/0.30/ver_0.302_manifest.json

@@ -0,0 +1,19 @@
+{
+    "version": "0.302",
+    "date": "2026-02-22",
+    "checksum_zip": "sha256:9a105e21eefa97b885d75f000be958e0604f119a01f0266ffc8ecdb34b346a7c",
+    "files": {
+        "modified": [
+            "autoload/Domain/Attribute/AttributeRepository.php",
+            "autoload/Domain/Product/ProductRepository.php",
+            "autoload/api/ApiRouter.php",
+            "autoload/api/Controllers/DictionariesApiController.php",
+            "autoload/api/Controllers/ProductsApiController.php"
+        ],
+        "added": [],
+        "deleted": []
+    },
+    "directories_deleted": [],
+    "sql": [],
+    "changelog": "NEW - REST API wariantow produktow (CRUD), slownik atrybutow, filtrowanie po atrybutach, wzbogacone atrybuty z tlumaczeniami"
+}