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>

languages/wp-prometheus-de_CH.po

@@ -317,6 +317,10 @@ msgstr "HTTP-Anfragedauer-Verteilung"
 msgid "Database queries by endpoint"
 msgstr "Datenbank-Abfragen nach Endpunkt"
 
+#: src/Admin/Settings.php
+msgid "Database query duration distribution (requires SAVEQUERIES)"
+msgstr "Datenbank-Abfragedauer-Verteilung (erfordert SAVEQUERIES)"
+
 #: src/Admin/Settings.php
 msgid "Scheduled cron events by hook"
 msgstr "Geplante Cron-Ereignisse nach Hook"

languages/wp-prometheus.pot

@@ -314,6 +314,10 @@ msgstr ""
 msgid "Database queries by endpoint"
 msgstr ""
 
+#: src/Admin/Settings.php
+msgid "Database query duration distribution (requires SAVEQUERIES)"
+msgstr ""
+
 #: src/Admin/Settings.php
 msgid "Scheduled cron events by hook"
 msgstr ""