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/common/job_error.go

@@ -0,0 +1,36 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Copyright 2021 The nektos/act Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package common
+
+import (
+	"context"
+)
+
+type jobErrorContextKey string
+
+const jobErrorContextKeyVal = jobErrorContextKey("job.error")
+
+// JobError returns the job error for current context if any
+func JobError(ctx context.Context) error {
+	val := ctx.Value(jobErrorContextKeyVal)
+	if val != nil {
+		if container, ok := val.(map[string]error); ok {
+			return container["error"]
+		}
+	}
+	return nil
+}
+
+func SetJobError(ctx context.Context, err error) {
+	if container, ok := ctx.Value(jobErrorContextKeyVal).(map[string]error); ok {
+		container["error"] = err
+	}
+}
+
+// WithJobErrorContainer adds a value to the context as a container for an error
+func WithJobErrorContainer(ctx context.Context) context.Context {
+	container := map[string]error{}
+	return context.WithValue(ctx, jobErrorContextKeyVal, container)
+}