build(nix): the tests of komorebi-macos-core run in linux-nextest and macos-nextest

nix/linux/flake-module.nix

@@ -147,6 +147,8 @@ in
                 "komorebi-layouts"
                 "komorebi-scrolling"
                 "komorebi-themes"
+                # the part of the macOS daemon that needs no macOS (nix/workspace-src.nix: linuxNeutralTests)
+                "komorebi-macos-core"
                 "komorebi-backend"
                 "komorebi-collections"
                 "komorebi-config"

nix/macos/build.nix

@@ -26,7 +26,7 @@ in
 
       lockFile = lib'.repoFile "Cargo.lock";
       tomlFile = lib'.repoFile "Cargo.toml";
-      packages = "-p komorebi -p komorebi-macos -p komorebic -p komorebi-client -p komorebi-bar";
+      packages = "-p komorebi -p komorebi-macos -p komorebi-macos-core -p komorebic -p komorebi-client -p komorebi-bar";
       workspaceArgs = {
         pname = "komorebi-workspace-macos";
         inherit version;

nix/workspace-src.nix

@@ -48,6 +48,12 @@ let
     "crates/komorebi-hotkeys"
   ];
   macosOnly = [ "crates/komorebi-macos" ];
+
+  # crates that no Linux package depends on, but whose tests need no macOS and so run in `linux-nextest`:
+  # the FFI-free part of the macOS daemon. They are not in linux/root-crates.json (that list is the
+  # `cargo tree` of the Linux packages, which tools/kde-closure-check keeps equal), only members of the
+  # Linux source.
+  linuxNeutralTests = [ "crates/komorebi-macos-core" ];
   windowsOnly = [
     "crates/komorebi-windows"
     "crates/komorebi-e2e-agent"
@@ -77,7 +83,7 @@ let
     nixgen = toolOnly;
     # everything but the other two platforms' crates and the tool
     windows = builtins.filter (m: !(builtins.elem m (linuxOnly ++ macosOnly ++ toolOnly))) allMembers;
-    linux = linuxOnly ++ linuxShared;
+    linux = linuxOnly ++ linuxShared ++ linuxNeutralTests;
     # everything but the Windows and Linux crates, the tool and the recorder
     macos = builtins.filter (
       m: !(builtins.elem m (windowsOnly ++ linuxOnly ++ toolOnly ++ [ "komorebi-recorder" ]))