[M8] cargoxx-pkgs as a flake: cargoxx add → string-form dep

Wrapper: fix cache.nixos.org-1 key; drop AppImage; pin publish to mozart/cargoxx-pkgs.

flake.nix

@@ -35,7 +35,7 @@
           experimental-features = nix-command flakes
           build-users-group =
           substituters = https://cache.cargoxx.amadey.xyz https://cache.nixos.org
-          trusted-public-keys = cache.cargoxx.amadey.xyz:HQNcKDh9lufWm0M32a06AEiLf1Hr0WoRY3Bp5NnWZxs= cache.nixos.org:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
+          trusted-public-keys = cache.cargoxx.amadey.xyz:HQNcKDh9lufWm0M32a06AEiLf1Hr0WoRY3Bp5NnWZxs= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
         '';
 
         cargoxx-bin = pkgs.gcc15Stdenv.mkDerivation {
@@ -53,9 +53,6 @@
           '';
           installPhase = ''
             mkdir -p $out/bin
-            # Codegen since Phase 1a routes every executable through
-            # RUNTIME_OUTPUT_DIRECTORY=${"$"}{CMAKE_BINARY_DIR}/bin, so
-            # the binary lives at build/release/bin/cargoxx.
             cp build/release/bin/cargoxx $out/bin/
             wrapProgram $out/bin/cargoxx \
               --prefix PATH : ${cargoxxRuntimePath} \
@@ -189,7 +186,6 @@
           '';
       in {
         packages.default = cargoxx-bin;
-        packages.appimage = bundlers-sys.toAppImage cargoxx-bin;
         packages.dockerImage = bundlers-sys.toDockerImage cargoxx-bin;
         packages.deb = bundlers-sys.toDEB cargoxx-bin;
         packages.rpm = bundlers-sys.toRPM cargoxx-bin;
@@ -197,7 +193,6 @@
 
         # Reusable packaging functions, all of the shape `drv -> drv`.
         # Mirror the `to*` naming used by github:NixOS/bundlers.
-        lib.toAppImage = bundlers-sys.toAppImage;
         lib.toDockerImage = bundlers-sys.toDockerImage;
         lib.toDEB = bundlers-sys.toDEB;
         lib.toRPM = bundlers-sys.toRPM;