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.

phpunit.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit
+    bootstrap="tests/bootstrap.php"
+    colors="true"
+    failOnWarning="false"
+    failOnRisky="false"
+>
+    <testsuites>
+        <testsuite name="Plugin Tests">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>