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/ProjectTabs.h

@@ -0,0 +1,73 @@
+#pragma once
+#include "Document/ProjectWorkspace.h"
+#include <QScrollArea>
+#include <QToolButton>
+#include <QWidget>
+
+// One tab: its title, the unsaved dot, its close button.
+class ProjectTabButton : public QWidget {
+    Q_OBJECT
+public:
+    ProjectTabButton(ProjectWorkspace &workspace, std::shared_ptr<ProjectTab> tab, QWidget *parent = nullptr);
+
+    const std::shared_ptr<ProjectTab> tab;
+    // What the session and the workspace hold, shown.
+    void synchronize();
+    bool isActive() const;
+
+protected:
+    void paintEvent(QPaintEvent *event) override;
+    void dragEnterEvent(QDragEnterEvent *event) override;
+    void dragMoveEvent(QDragMoveEvent *event) override;
+    void dragLeaveEvent(QDragLeaveEvent *event) override;
+    void dropEvent(QDropEvent *event) override;
+
+private:
+    bool acceptsDrop(const QMimeData &data) const;
+    void setTargeted(bool targeted);
+
+    ProjectWorkspace &m_workspace;
+    QToolButton *const m_select;
+    QToolButton *const m_close;
+    bool m_targeted = false;
+};
+
+// Swift's NewProjectDropTarget: the New canvas button takes drops.
+class NewCanvasButton : public QToolButton {
+    Q_OBJECT
+public:
+    explicit NewCanvasButton(ProjectWorkspace &workspace, QWidget *parent = nullptr);
+
+protected:
+    void paintEvent(QPaintEvent *event) override;
+    void dragEnterEvent(QDragEnterEvent *event) override;
+    void dragMoveEvent(QDragMoveEvent *event) override;
+    void dragLeaveEvent(QDragLeaveEvent *event) override;
+    void dropEvent(QDropEvent *event) override;
+
+private:
+    bool acceptsDrop(const QMimeData &data) const;
+    void setTargeted(bool targeted);
+
+    ProjectWorkspace &m_workspace;
+    bool m_targeted = false;
+};
+
+// The row of tabs, one a project, scrolling when long.
+class ProjectTabStrip : public QScrollArea {
+    Q_OBJECT
+public:
+    explicit ProjectTabStrip(ProjectWorkspace &workspace, QWidget *parent = nullptr);
+
+    QList<ProjectTabButton *> buttons() const;
+
+protected:
+    bool eventFilter(QObject *watched, QEvent *event) override;
+
+private:
+    void synchronize();
+    void showFront();
+
+    ProjectWorkspace &m_workspace;
+    QWidget *const m_row;
+};