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.

tests/ModelExclusionsTest.php

@@ -0,0 +1,17 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+
+class ModelExclusionsTest extends TestCase {
+	public function test_ensure_allowed_blocks_excluded_model() {
+		$blocked = Groq_AI_Model_Exclusions::ensure_allowed( 'groq', 'whisper-large-v3' );
+		$this->assertSame( '', $blocked );
+	}
+
+	public function test_filter_models_removes_excluded_entries() {
+		$models = [ 'llama3-70b-8192', 'whisper-large-v3', 'mixtral-8x7b-32768' ];
+		$filtered = Groq_AI_Model_Exclusions::filter_models( 'groq', $models );
+
+		$this->assertSame( [ 'llama3-70b-8192', 'mixtral-8x7b-32768' ], $filtered );
+	}
+}