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/Installer.php

@@ -63,6 +63,7 @@ final class Installer {
             'wp_prometheus_auth_token',
             'wp_prometheus_enable_default_metrics',
             'wp_prometheus_enabled_metrics',
+            'wp_prometheus_runtime_metrics',
         );
 
         foreach ( $options as $option ) {