fix(notifications): report a version in GetServerInformation

[UfukUstali]

Problem

The freedesktop notifications GetServerInformation method returns an empty version string:

$ gdbus call --session \
    --dest org.freedesktop.Notifications \
    --object-path /org/freedesktop/Notifications \
    --method org.freedesktop.Notifications.GetServerInformation
('quickshell', 'quickshell', '', '1.2')

The third field (the server version) is empty. NotificationServer::GetServerInformation sources it from QCoreApplication::applicationVersion(), but main() only ever calls setApplicationName("quickshell") and never sets the application version, so applicationVersion() returns an empty string.

This isn't purely cosmetic: some clients treat a notification server with missing/empty server information as incomplete or non-conformant. For example, Chrome checks the server info when deciding whether to route native notifications through the freedesktop server, and an empty version can cause it to reject quickshell as a usable notification target. This results in Chrome creating it's own windows as a fallback mechanism for notifications.

Fix

Set the application version from the already-available QS_VERSION macro in main(), right after the application name is set. build.hpp (which defines QS_VERSION) is already included by main.cpp, so this is self-contained.

QCoreApplication::setApplicationName("quickshell");
QCoreApplication::setApplicationVersion(QS_VERSION);

After the change, GetServerInformation returns the real version:

('quickshell', 'quickshell', '0.3.0', '1.2')

Testing

Verified GetServerInformation over D-Bus now reports the version string instead of an empty field and Chrome notifications working.

Notes

I used plain QS_VERSION rather than the richer QS_VERSION " (revision " GIT_REVISION ...) format from debuginfo.cpp, to keep the D-Bus version field to a clean semver value — happy to switch to the fuller format if you'd prefer consistency with the debug output.