Add private sequence-item placement

internal/engine/layered.go

@@ -4,10 +4,11 @@ import "os"
 
 // Input selects one source, its destination, and its independent import policy.
 type Input struct {
-	Source      Source
-	Imports     bool
-	Filesystem  *FilesystemContext
-	Destination Path
+	Source        Source
+	Imports       bool
+	Filesystem    *FilesystemContext
+	Destination   Path
+	placementMode placementMode
 }
 
 // Underlay contains strictly composed contributions at one precedence tier.
@@ -36,7 +37,7 @@ func LoadLayered[T any](main Input, secrets SecretBinding, supplied ...LayeredOp
 	request := loadRequest[T]{
 		main: loadInput{
 			source: main.Source, imports: main.Imports, filesystem: main.Filesystem,
-			destination: main.Destination.clone(),
+			destination: main.Destination.clone(), placementMode: main.placementMode,
 		},
 		definition: options.Definition, sourceVersionMode: options.SourceVersionMode,
 		overlay:           options.Overlay,
@@ -49,7 +50,7 @@ func LoadLayered[T any](main Input, secrets SecretBinding, supplied ...LayeredOp
 		for inputIndex, input := range underlay.Inputs {
 			request.underlays[index].inputs[inputIndex] = loadInput{
 				source: input.Source, imports: input.Imports, filesystem: input.Filesystem,
-				destination: input.Destination.clone(),
+				destination: input.Destination.clone(), placementMode: input.placementMode,
 			}
 		}
 	}