OmaPhoto 1.0.0: the Linux port of Compositor

A layered image editor for Linux and Omarchy, ported from Compositor
(github.com/robbietilton/Compositor), whose Swift source is its
specification. It reads and writes Compositor's .comp projects.

Packages for Ubuntu, Fedora and Arch come from the release workflow;
scripts/install/ holds one install script per distribution family,
and flake.nix serves NixOS.

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

src/UI/BlendModePicker.h

@@ -0,0 +1,23 @@
+#pragma once
+#include "Document/EditorSession.h"
+#include <QComboBox>
+
+// The blend menu: hovering tries a mode, choosing keeps it.
+class BlendModePicker : public QComboBox {
+    Q_OBJECT
+public:
+    explicit BlendModePicker(EditorSession &session, QWidget *parent = nullptr);
+
+    void showPopup() override;
+    void hidePopup() override;
+
+private:
+    void synchronize();
+    void highlight(int index);
+    void choose(int index);
+
+    EditorSession &m_session;
+    bool m_tracking = false;
+    std::optional<QUuid> m_layerID;
+    std::optional<LayerBlendMode> m_highlighted;
+};