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/LevelsAutomatic.h

@@ -0,0 +1,13 @@
+#pragma once
+#include "Document/Levels.h"
+
+// What a Levels eyedropper sets: black, gray or white point.
+enum class LevelsSample { black, gray, white };
+inline constexpr std::array<LevelsSample, 3> allLevelsSamples{LevelsSample::black, LevelsSample::gray, LevelsSample::white};
+QString rawValue(LevelsSample sample);
+
+// Swift's LevelsAuto: settings read from a histogram.
+enum class LevelsAuto { contrast, color, neutral };
+inline constexpr std::array<LevelsAuto, 3> allLevelsAutos{LevelsAuto::contrast, LevelsAuto::color, LevelsAuto::neutral};
+QString rawValue(LevelsAuto mode);
+LevelsSettings settings(LevelsAuto mode, const LevelsHistogram &histogram);