gui: ship the real icon set, wire toolbar/tray/window icon, rebase onto main

Adwaita-derived (GNOME Project, LGPL-3-or-CC-BY-SA), recoloured per light/dark
skin and laid out in IDM's toolbar positions per docs/03-gui-spec.md §1.
Licence and per-file provenance recorded in gui/resources/icons/LICENSE.

New IconTheme mirrors ThemeManager's colorSchemeChanged hook so a live
light/dark switch swaps every action's glyph, not just the QSS. Toolbar/menu
actions, the tray icon and the window icon all now use it instead of the
SP_ArrowDown placeholder. Install-path notes for PKG filed as R5 in
gui/docs/pkg-qa-requests-m1.md.

Also rebases lane/gui onto main (13 commits, no gui/ conflicts).

Verified: full build clean, all 13 gui ctest targets pass (including
gui_no_download_logic), unhappy-path DoD gate PASS against mockd
(--drop-connection).

Co-Authored-By: Claude Sonnet 5 <[email protected]>

gui/src/mainwindow/MainWindow.cpp

@@ -37,6 +37,7 @@
 #include "rpc/RpcClient.hpp"
 #include "tray/TrayIcon.hpp"
 #include "util/Format.hpp"
+#include "util/IconTheme.hpp"
 #include "util/Theme.hpp"
 #include "widgets/DropTargetWidget.hpp"
 #include "widgets/ProgressDelegate.hpp"
@@ -67,8 +68,12 @@ MainWindow::MainWindow(rpc::RpcClient *client, QWidget *parent)
       offlineBanner_(new QWidget(this)),
       countsTimer_(new QTimer(this)) {
     setWindowTitle(tr("Velox Download Manager"));
+    setWindowIcon(IconTheme::appIcon());
     resize(1040, 600);
 
+    iconTheme_ = new IconTheme(this);
+    connect(iconTheme_, &IconTheme::iconsChanged, this, &MainWindow::applyIcons);
+
     proxy_->setSourceModel(model_);
     proxy_->setSortCaseSensitivity(Qt::CaseInsensitive);
 
@@ -116,6 +121,7 @@ MainWindow::MainWindow(rpc::RpcClient *client, QWidget *parent)
     setCentralWidget(central);
 
     buildActions();
+    applyIcons();
     buildMenus();
     buildToolBar();
     buildTray();
@@ -205,6 +211,24 @@ void MainWindow::buildActions() {
     connect(actShow_, &QAction::triggered, this, &MainWindow::showAndRaise);
 }
 
+// gui/resources/icons/LICENSE: toolbar-position -> icon-stem mapping. Re-run on
+// IconTheme::iconsChanged so a live light/dark switch swaps every action's glyph, the
+// same way ThemeManager swaps the QSS on the same signal.
+void MainWindow::applyIcons() {
+    actAddUrl_->setIcon(IconTheme::icon(QStringLiteral("add-url")));
+    actResume_->setIcon(IconTheme::icon(QStringLiteral("resume")));
+    actPause_->setIcon(IconTheme::icon(QStringLiteral("pause")));
+    actStop_->setIcon(IconTheme::icon(QStringLiteral("stop-all")));
+    actRemove_->setIcon(IconTheme::icon(QStringLiteral("delete")));
+    actResumeAll_->setIcon(IconTheme::icon(QStringLiteral("resume")));
+    actPauseAll_->setIcon(IconTheme::icon(QStringLiteral("pause")));
+    actProperties_->setIcon(IconTheme::icon(QStringLiteral("properties")));
+    actOptions_->setIcon(IconTheme::icon(QStringLiteral("options")));
+    actScheduler_->setIcon(IconTheme::icon(QStringLiteral("scheduler")));
+    actBatch_->setIcon(IconTheme::icon(QStringLiteral("batch")));
+    actGrabber_->setIcon(IconTheme::icon(QStringLiteral("grabber")));
+}
+
 void MainWindow::buildMenus() {
     QMenu *tasks = menuBar()->addMenu(tr("&Tasks"));
     tasks->addAction(actAddUrl_);

gui/src/mainwindow/MainWindow.hpp

@@ -27,6 +27,7 @@ class DownloadTableModel;
 class CategoryPanel;
 class TrayIcon;
 class DropTargetWidget;
+class IconTheme;
 #ifdef VELOX_GUI_HAVE_DBUS
 class GlobalShortcut;
 #endif
@@ -69,6 +70,7 @@ class MainWindow : public QMainWindow {
     void showAndRaise();
     void onSettingsChanged(const QJsonObject &params);
     void onUrlDropped(const QString &url);
+    void applyIcons();
 
   private:
     void buildActions();
@@ -107,6 +109,7 @@ class MainWindow : public QMainWindow {
 
     QJsonArray categoriesCache_;
     QJsonArray queuesCache_;
+    IconTheme *iconTheme_ = nullptr;
     TrayIcon *trayIcon_ = nullptr;
     DropTargetWidget *dropTarget_ = nullptr;
     bool minimizeToTrayEnabled_ = false;