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/IO/ImageImporter.h

@@ -0,0 +1,48 @@
+#pragma once
+#include <QImage>
+#include <QString>
+#include <compare>
+#include <memory>
+#include <stdexcept>
+
+class RasterSnapshot;
+
+// Which pixels an asset holds, as CGImage identity did.
+struct ImageIdentity {
+    const RasterSnapshot *raster = nullptr;
+    qint64 cacheKey = 0;
+    auto operator<=>(const ImageIdentity &) const = default;
+};
+
+class ImportedImage {
+public:
+    ImportedImage(QImage image, QImage thumbnail, QString name);
+    ImportedImage(std::shared_ptr<const RasterSnapshot> raster, QImage thumbnail, QString name);
+
+    QSize size() const;
+    // Painted tiles flatten on first use.
+    QImage image() const;
+    ImageIdentity identity() const;
+    qint64 byteCount() const;
+
+    QImage thumbnail;
+    QString name;
+    std::shared_ptr<const RasterSnapshot> raster;
+
+private:
+    QImage m_image;
+};
+
+class ImageImportError : public std::runtime_error {
+public:
+    enum class Kind { unreadable, unsupported, tooLarge };
+    explicit ImageImportError(Kind kind);
+    Kind kind;
+};
+
+namespace ImageImporter {
+// Qt refuses decodes over 128 MB; the app's budgets rule.
+void liftAllocationLimit();
+// JPEG, PNG, TIFF or HEIC: upright, sRGB, premultiplied.
+ImportedImage decode(const QString &path, qint64 remainingPixels = 100'000'000);
+}