internal/rosa: create metadata alongside artifact

This enables deferring evaluation of azalea-based packages and fixes the longstanding quirk of version being disjoint from other metadata.

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

internal/rosa/rosa.go

@@ -249,7 +249,7 @@ func (t Toolchain) New(
 		support = append(support, extra...)
 		support = append(support, cureEtc{})
 		if t.stage == stageEarly {
-			a, _ := t.Load(stage0Dist)
+			_, a := t.MustLoad(stage0Dist)
 			support = append(support, a)
 		} else {
 			support = append(support, t.S.New(_stageBusybox).New("gentoo", 0, nil, nil, nil, `
@@ -438,10 +438,11 @@ func (t Toolchain) appendHandle(a []pkg.Artifact, pv pa, p ArtifactH) []pkg.Arti
 	}
 	pv[p] = struct{}{}
 
-	for _, d := range t.MustGet(p).Dependencies {
+	meta, _ := t.MustLoad(p)
+	for _, d := range meta.Dependencies {
 		a = t.appendHandle(a, pv, d)
 	}
-	d, _ := t.Load(p)
+	_, d := t.MustLoad(p)
 	return append(a, d)
 }