feat: Add runtime metrics for HTTP requests and database queries (v0.1.0)

- Add RuntimeCollector class for tracking request lifecycle metrics
- Add wordpress_http_requests_total counter (method, status, endpoint)
- Add wordpress_http_request_duration_seconds histogram
- Add wordpress_db_queries_total counter (endpoint)
- Add wordpress_db_query_duration_seconds histogram (requires SAVEQUERIES)
- Update Collector to expose stored runtime metrics
- Add new settings options for enabling/disabling runtime metrics
- Create translation files (.pot, .po, .mo) for internationalization
- Update documentation and changelog

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Plugin.php

@@ -11,6 +11,7 @@ use Magdev\WpPrometheus\Admin\Settings;
 use Magdev\WpPrometheus\Endpoint\MetricsEndpoint;
 use Magdev\WpPrometheus\License\Manager as LicenseManager;
 use Magdev\WpPrometheus\Metrics\Collector;
+use Magdev\WpPrometheus\Metrics\RuntimeCollector;
 
 // Prevent direct file access.
 if ( ! defined( 'ABSPATH' ) ) {
@@ -90,6 +91,20 @@ final class Plugin {
             new Settings();
         }
 
+        // Initialize runtime collector for request metrics (always runs to collect data).
+        // Only collect if at least one runtime metric is enabled.
+        $enabled_metrics  = get_option( 'wp_prometheus_enabled_metrics', array() );
+        $runtime_metrics  = array(
+            'wordpress_http_requests_total',
+            'wordpress_http_request_duration_seconds',
+            'wordpress_db_queries_total',
+        );
+        $has_runtime_metrics = ! empty( array_intersect( $runtime_metrics, $enabled_metrics ) );
+
+        if ( $has_runtime_metrics && LicenseManager::is_license_valid() ) {
+            RuntimeCollector::get_instance();
+        }
+
         // Initialize metrics endpoint (only if licensed).
         if ( LicenseManager::is_license_valid() ) {
             $this->collector = new Collector();