refactor: move act under internal

The runner is an application, not a library. `act/model` and
`act/exprparser` were the last packages anything outside this repository
consumed and they now live in actionslib, so nothing needs the rest of
`act` to be importable, and keeping it importable invites the coupling
that was just removed.

Import paths only, the files are unchanged.

Assisted-by: Codet:GPT-5.1-Codex

internal/act/container/docker_images.go

@@ -0,0 +1,64 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// Copyright 2020 The nektos/act Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:build !(WITHOUT_DOCKER || !(linux || darwin || windows || netbsd))
+
+package container
+
+import (
+	"context"
+	"fmt"
+
+	cerrdefs "github.com/containerd/errdefs"
+	"github.com/moby/moby/client"
+)
+
+// ImageExistsLocally returns a boolean indicating if an image with the
+// requested name, tag and architecture exists in the local docker image store
+func ImageExistsLocally(ctx context.Context, imageName, platform string) (bool, error) {
+	cli, err := GetDockerClient(ctx)
+	if err != nil {
+		return false, err
+	}
+	defer cli.Close()
+
+	inspectImage, err := cli.ImageInspect(ctx, imageName)
+	if cerrdefs.IsNotFound(err) {
+		return false, nil
+	} else if err != nil {
+		return false, err
+	}
+
+	if platform == "" || platform == "any" || fmt.Sprintf("%s/%s", inspectImage.Os, inspectImage.Architecture) == platform {
+		return true, nil
+	}
+
+	return false, nil
+}
+
+// RemoveImage removes image from local store, the function is used to run different
+// container image architectures
+func RemoveImage(ctx context.Context, imageName string, force, pruneChildren bool) (bool, error) {
+	cli, err := GetDockerClient(ctx)
+	if err != nil {
+		return false, err
+	}
+	defer cli.Close()
+
+	inspectImage, err := cli.ImageInspect(ctx, imageName)
+	if cerrdefs.IsNotFound(err) {
+		return false, nil
+	} else if err != nil {
+		return false, err
+	}
+
+	if _, err = cli.ImageRemove(ctx, inspectImage.ID, client.ImageRemoveOptions{
+		Force:         force,
+		PruneChildren: pruneChildren,
+	}); err != nil {
+		return false, err
+	}
+
+	return true, nil
+}