fix(test): give the tiered-server harness a real storage view (v0.102.0 follow-up)

v0.102.0 defers a tier whose target storage is absent. The Slice A harness used
fakeStorage{} with NO targets, so after that change it deferred every tier and
five Slice A assertions became vacuous failures.

The product behaviour is correct; the harness never modelled a real box, which
has both storages present. Fixed by giving it local + felhom-pbs.

My error, and worth naming: I ran the suite and committed in the same command,
read 'packages ok: 28' and pushed without checking rc=1. That is exactly the
exit-code trap recorded in this arc twice already.

Full agent suite green: rc=0, 29 packages.

internal/localapi/backup_tiers_test.go

@@ -28,7 +28,13 @@ func tieredServer(t *testing.T, st *fakeStore, localSvc, pbsSvc *fakeBackups) *S
 		Guests:     &fakeGuests{},
 		Backups:    localSvc,
 		Store: st,
-		Storage:    fakeStorage{},
+		// Both tier targets must be PRESENT in the storage view: since v0.102.0 a tier whose target
+		// storage is absent DEFERS. A real box has both; a fake with no targets would silently
+		// defer every tier and make these assertions vacuous.
+		Storage: fakeStorage{targets: []hub.StorageTarget{
+			{Name: "local", Type: "local"},
+			{Name: "felhom-pbs", Type: "pbs"},
+		}},
 		Tokens: staticTokens{"A": 8200, "B": 9300},
 		BackupTiers: []BackupTier{
 			{TargetID: "local", Cadence: 24 * time.Hour, Primary: true, Service: localSvc},