docs: Add database query timing documentation and dashboard panel (v0.4.7)

- Add Query Duration Distribution panel to Grafana Runtime dashboard
- Add wordpress_db_query_duration_seconds to Help tab metrics reference
- Add SAVEQUERIES documentation section to README
- Update translation files with new strings

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

CHANGELOG.md

@@ -5,6 +5,19 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.4.7] - 2026-02-03
+
+### Added
+
+- Database query duration distribution panel in Grafana Runtime dashboard
+- `wordpress_db_query_duration_seconds` metric now listed in Help tab
+- Documentation for enabling `SAVEQUERIES` constant for query timing
+
+### Changed
+
+- Updated README with instructions for enabling database query timing
+- Grafana Runtime dashboard now includes bucket distribution chart for DB queries
+
 ## [0.4.6] - 2026-02-03
 
 ### Added