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-site-metadata.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * Basic unit test for site-metadata endpoint
+ *
+ * @package Igny8Bridge
+ */
+
+class Test_Site_Metadata_Endpoint extends WP_UnitTestCase {
+
+    public function test_site_metadata_endpoint_returns_success() {
+        // Ensure connection enabled
+        update_option('igny8_connection_enabled', 1);
+
+        // Create a fake API key so permission checks pass via Igny8API
+        update_option('igny8_api_key', 'test-api-key-123');
+        update_option('igny8_access_token', 'test-api-key-123');
+
+        // Build request
+        $request = new WP_REST_Request('GET', '/igny8/v1/site-metadata/');
+        $request->set_header('Authorization', 'Bearer test-api-key-123');
+
+        $server = rest_get_server();
+        $response = $server->dispatch($request);
+
+        $this->assertEquals(200, $response->get_status());
+        $data = $response->get_data();
+        $this->assertNotEmpty($data);
+        $this->assertArrayHasKey('success', $data);
+        $this->assertTrue($data['success']);
+        $this->assertArrayHasKey('data', $data);
+        $this->assertArrayHasKey('post_types', $data['data']);
+        $this->assertArrayHasKey('taxonomies', $data['data']);
+    }
+}
+
+