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/LiveLayerMask.h

@@ -0,0 +1,12 @@
+#pragma once
+#include "IO/ProjectStore.h"
+#include <vector>
+
+namespace LiveMaskGraph {
+void validate(const std::vector<ProjectLayerRecord> &layers);
+}
+
+namespace LiveMaskBaker {
+// The target's pixels through its live mask; nil without pixels.
+std::optional<ImportedImage> bake(const ProjectSnapshot &snapshot, QUuid target);
+}