About dialog: fix unreadable dark-mode text and missing version

The subtitle and version line used palette(mid), a role meant for 3D
bevel/shadow decoration, not text -- it has poor contrast against the
window background in dark themes. Replaced with a color blended from
the widget's actual text/window palette colors, so it stays readable
(de-emphasized but never low-contrast) in either theme.

Also: QCoreApplication::applicationVersion() was never being set
anywhere, so the dialog always showed "Development build" regardless
of the actual built version. CMake's PROJECT_VERSION is now exposed
to the app via a compile definition and wired into
setApplicationVersion() at startup.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/about_dialog.cpp

@@ -8,6 +8,31 @@
 #include <QTextBrowser>
 #include <QVBoxLayout>
 
+namespace {
+// palette(mid) is meant for 3D bevel/shadow decoration, not text — it has
+// poor contrast against the window background in dark themes (barely
+// legible). Blend the widget's actual text and window colors instead, so
+// the result is reliably readable — de-emphasized relative to full-strength
+// text, but never low-contrast — in either a light or dark theme.
+QColor mutedTextColor(const QWidget* widget)
+{
+    const QPalette pal = widget->palette();
+    const QColor text = pal.color(QPalette::WindowText);
+    const QColor background = pal.color(QPalette::Window);
+    constexpr qreal kTextWeight = 0.65;
+
+    auto blend = [kTextWeight](int textChannel, int backgroundChannel) {
+        return qBound(0,
+                      qRound(textChannel * kTextWeight + backgroundChannel * (1.0 - kTextWeight)),
+                      255);
+    };
+
+    return QColor(blend(text.red(), background.red()),
+                  blend(text.green(), background.green()),
+                  blend(text.blue(), background.blue()));
+}
+}
+
 AboutDialog::AboutDialog(QWidget* parent) : QDialog(parent)
 {
     setWindowTitle(QStringLiteral("About OrbitHub"));
@@ -34,7 +59,7 @@ AboutDialog::AboutDialog(QWidget* parent) : QDialog(parent)
         QStringLiteral("Unified remote session manager for SSH, RDP, and VNC workflows."),
         this);
     subtitle->setWordWrap(true);
-    subtitle->setStyleSheet(QStringLiteral("color: palette(mid);"));
+    subtitle->setStyleSheet(QStringLiteral("color: %1;").arg(mutedTextColor(this).name()));
 
     const QString version = QCoreApplication::applicationVersion().trimmed().isEmpty()
         ? QStringLiteral("Development build")
@@ -42,7 +67,7 @@ AboutDialog::AboutDialog(QWidget* parent) : QDialog(parent)
     auto* buildLine = new QLabel(
         QStringLiteral("Version: %1 | Qt runtime linked dynamically").arg(version),
         this);
-    buildLine->setStyleSheet(QStringLiteral("color: palette(mid);"));
+    buildLine->setStyleSheet(QStringLiteral("color: %1;").arg(mutedTextColor(this).name()));
 
     titleColumn->addWidget(title);
     titleColumn->addWidget(subtitle);

src/main.cpp

@@ -10,6 +10,9 @@ int main(int argc, char* argv[])
     QApplication app(argc, argv);
     app.setOrganizationName(QStringLiteral("FireBugIT"));
     app.setApplicationName(QStringLiteral("OrbitHub"));
+#ifdef ORBITHUB_VERSION_STRING
+    app.setApplicationVersion(QStringLiteral(ORBITHUB_VERSION_STRING));
+#endif
     app.setWindowIcon(createOrbitHubAppIcon());
 
     SessionWindow window;