feat: add NewContext helper (by AI)

jsmod.go

@@ -20,6 +20,14 @@ func Get(ctx context.Context, key string) any {
 	return nil
 }
 
+// NewContext returns a new context with the provided injection map.
+func NewContext(parent context.Context, injects map[string]any) context.Context {
+	if parent == nil {
+		parent = context.Background()
+	}
+	return context.WithValue(parent, internalContextKey, injects)
+}
+
 // IsSafeMode checks if the provided context indicates that the execution is in safe mode.
 func IsSafeMode(ctx context.Context) bool {
 	if sm, ok := Get(ctx, "SafeMode").(bool); ok {