[Client] Settings: sub-page rows deep-linking into page sections (#7487)

Add AbstractSettingsPage::getSections built from each page's group boxes.
Show each multi-group page's sections as child rows in the navigation
tree. Section rows show the parent page and scroll to and highlight the
group box. Start pages collapsed. Keep single-group pages flat.

Reworked to stay in the enlarged modal instead of the settings tab.

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

cockatrice/src/interface/widgets/settings_page/abstract_settings_page.h

@@ -2,6 +2,7 @@
 #define COCKATRICE_ABSTRACT_SETTINGS_PAGE_H
 
 #include <QList>
+#include <QString>
 #include <QWidget>
 #include <qtmetamacros.h>
 
@@ -11,12 +12,28 @@
 
 struct SettingsSearchEntry;
 
+/**
+ * @brief A navigable section of a settings page (one group box)
+ */
+struct SettingsPageSection
+{
+    QString title;                    ///< Translated group title
+    QWidget *sectionWidget = nullptr; ///< Group box to scroll to and highlight
+};
+
 class AbstractSettingsPage : public QWidget
 {
     Q_OBJECT
 public:
     virtual void retranslateUi() = 0;
     virtual QList<SettingsSearchEntry> getSearchEntries();
+    /**
+     * @brief Sections of this page for sub-page navigation, in display order
+     *
+     * Scans the page's direct-child group boxes; pages with a single group
+     * report no sections so the nav stays flat for them.
+     */
+    QList<SettingsPageSection> getSections();
 
 protected:
     static QList<SettingsSearchEntry> autoDetectSearchEntries(QWidget *page, int pageIndex);