Lettore: margini configurabili (Settings.readerMargin + Slider nelle impostazioni, iniettati nello stile del capitolo) + controlli in PushUpMenu (un solo trascinamento in alto)

src/settings.cpp

@@ -66,6 +66,20 @@ void Settings::setIgnoreSslErrors(bool value)
     emit ignoreSslErrorsChanged();
 }
 
+int Settings::readerMargin() const
+{
+    return m_settings.value(QStringLiteral("readerMargin"), 24).toInt();
+}
+
+void Settings::setReaderMargin(int value)
+{
+    if (value == readerMargin())
+        return;
+    m_settings.setValue(QStringLiteral("readerMargin"), value);
+    m_settings.sync();
+    emit readerMarginChanged();
+}
+
 QString Settings::downloadDir() const
 {
     QString dir = QStandardPaths::writableLocation(QStandardPaths::DownloadLocation);