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/dryrun.go

@@ -0,0 +1,29 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Copyright 2020 The nektos/act Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package common
+
+import (
+	"context"
+)
+
+type dryrunContextKey string
+
+const dryrunContextKeyVal = dryrunContextKey("dryrun")
+
+// Dryrun returns true if the current context is dryrun
+func Dryrun(ctx context.Context) bool {
+	val := ctx.Value(dryrunContextKeyVal)
+	if val != nil {
+		if dryrun, ok := val.(bool); ok {
+			return dryrun
+		}
+	}
+	return false
+}
+
+// WithDryrun adds a value to the context for dryrun
+func WithDryrun(ctx context.Context, dryrun bool) context.Context {
+	return context.WithValue(ctx, dryrunContextKeyVal, dryrun)
+}