internal/rosa: pass stage alongside state

This cleans up many function signatures.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/report.go

@@ -32,12 +32,13 @@ func WriteReport(msg message.Msg, w io.Writer, c *pkg.Cache) error {
 		zero [wordSize]byte
 		buf  [len(pkg.ID{}) + wordSize]byte
 	)
+	t := native.Std()
 	for _, p := range native.Collect() {
-		a, _ := native.Load(Std, p)
 		meta := native.Get(p)
 		if meta == nil {
 			return errors.New("artifact " + p.String() + " in inconsistent state")
 		}
+		a, _ := t.MustLoad(p)
 		if _, ok := a.(pkg.FileArtifact); ok {
 			msg.Verbosef("skipping file artifact %s", meta.Name)
 			continue