Add core classes and tests for Groq AI compatibility, logging, and model services

- Implement Groq_AI_Compatibility_Service to manage WooCommerce dependency and admin notices.
- Create Groq_AI_Log_Scheduler for scheduled log cleanup based on settings.
- Develop Groq_AI_Model_Service for model selection and caching.
- Add language translations in POT file for Dutch.
- Set up PHPUnit configuration and bootstrap for testing.
- Implement unit tests for model exclusions, provider request building, settings management, and term saving functionality.

composer.json

@@ -0,0 +1,16 @@
+{
+  "name": "sitiweb/siti-ai-product-content-generator",
+  "description": "SitiAI Product Teksten WordPress plugin",
+  "type": "wordpress-plugin",
+  "require-dev": {
+    "phpunit/phpunit": "^9.6"
+  },
+  "autoload-dev": {
+    "classmap": [
+      "includes/"
+    ]
+  },
+  "scripts": {
+    "test": "phpunit"
+  }
+}