Add Site Metadata Endpoint and API Key Management

- Introduced a new Site Metadata endpoint (`GET /wp-json/igny8/v1/site-metadata/`) for retrieving available post types and taxonomies, including counts.
- Added API key input in the admin settings for authentication, with secure storage and revocation functionality.
- Implemented a toggle for enabling/disabling two-way sync operations.
- Updated documentation to reflect new features and usage examples.
- Enhanced permission checks for REST API calls to ensure secure access.

igny8-wp-integration-plugin/tests/test-revoke-api-key.php

@@ -0,0 +1,28 @@
+<?php
+/**
+ * Unit test for API key revoke handler
+ *
+ * @package Igny8Bridge
+ */
+
+class Test_Revoke_Api_Key extends WP_UnitTestCase {
+
+    public function test_revoke_api_key_clears_options() {
+        // Simulate stored API key and tokens
+        update_option('igny8_api_key', 'test-key-123');
+        update_option('igny8_access_token', 'test-key-123');
+        update_option('igny8_refresh_token', 'refresh-123');
+        update_option('igny8_token_refreshed_at', time());
+
+        // Call revoke
+        Igny8Admin::revoke_api_key();
+
+        // Assert removed
+        $this->assertFalse(get_option('igny8_api_key'));
+        $this->assertFalse(get_option('igny8_access_token'));
+        $this->assertFalse(get_option('igny8_refresh_token'));
+        $this->assertFalse(get_option('igny8_token_refreshed_at'));
+    }
+}
+
+