Forward Scriptorium credentials through the shared adapter path

internal/adapters/scriptorium/fake.go

@@ -3,6 +3,7 @@ package scriptorium
 import (
 	"context"
 	"fmt"
+	"slices"
 
 	"gitea.maximumdirect.net/eric/narratio/internal/fileops"
 )
@@ -65,6 +66,7 @@ func (f *FakeRunner) RunArtifact(ctx context.Context, req RunArtifactRequest) (A
 	if err := ctx.Err(); err != nil {
 		return ArtifactResult{}, err
 	}
+	req.Credentials = slices.Clone(req.Credentials)
 	f.RunRequests = append(f.RunRequests, req)
 	if f.RunErr != nil {
 		return ArtifactResult{}, f.RunErr
@@ -105,6 +107,7 @@ func (f *FakeRunner) RenderArtifact(ctx context.Context, req RenderArtifactReque
 	if err := ctx.Err(); err != nil {
 		return ArtifactResult{}, err
 	}
+	req.Credentials = slices.Clone(req.Credentials)
 	f.RenderRequests = append(f.RenderRequests, req)
 	if f.RenderErr != nil {
 		return ArtifactResult{}, f.RenderErr