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/Document/ShapeTool+Session.h

@@ -0,0 +1,31 @@
+// Swift's ShapeTool extension: shapes dragged out as new layers.
+public:
+    // Pixels one shape layer may hold, an import's budget.
+    static constexpr qint64 maxShapePixels = 100'000'000;
+    ShapeKind shapeKind() const { return m_shapeKind; }
+    void setShapeKind(ShapeKind kind);
+    // A rectangle's corner radius, in pixels; 0 keeps corners square.
+    double shapeCornerRadius() const { return m_shapeCornerRadius; }
+    void setShapeCornerRadius(double radius);
+    // A line's thickness, in document pixels.
+    double shapeLineWidth() const { return m_shapeLineWidth; }
+    void setShapeLineWidth(double width);
+    const std::optional<ShapeDraft> &shapeDraft() const { return m_shapeDraft; }
+    void beginShape(QPointF point);
+    // The line being dragged, from its start to the pointer.
+    std::optional<std::pair<QPointF, QPointF>> shapeLineEnds() const;
+    // Shift squares or snaps a line; Alt grows from centre.
+    void dragShape(QPointF point, bool square, bool fromCenter);
+    void cancelShape();
+    // Shift-U and Tab: Rectangle, Ellipse, Line.
+    void toggleShapeKind();
+    // The draft becomes a layer above the active one.
+    void finishShape();
+    // "Rectangle 1", "Ellipse 2", skipping names already used.
+    QString nextShapeName(ShapeKind kind) const;
+    // A resized shape layer draws its shape again.
+    void redrawShape(int index);
+    // A rounded rectangle at its dragged size, 2048 at most.
+    QImage shapeTransformPreview(const ImageLayer &layer, const LayerTransform &transform) const;
+    static QImage shapeImage(ShapeKind kind, QSizeF size, const PaletteColor &color, double cornerRadius = 0, double lineWidth = 0,
+                             std::optional<QPointF> start = std::nullopt, std::optional<QPointF> end = std::nullopt);