feat: flag Ubuntu phased updates and leave them out of pending counts

apt lists phased updates as upgradable, but an upgrade defers them until the
host is selected. A simulated upgrade names them; they are reported with the
phased flag (vantage-shared v0.6.0) and not counted in pending_after.

internal/sync/patch.go

@@ -120,12 +120,12 @@ func reportPendingUpdates(cfg *config.Config) int {
 	}
 	list := make([]pb.PackageUpdate, len(pkgs))
 	for i, p := range pkgs {
-		list[i] = pb.PackageUpdate{Name: p.Name, CurrentVersion: p.CurrentVersion, NewVersion: p.NewVersion}
+		list[i] = pb.PackageUpdate{Name: p.Name, CurrentVersion: p.CurrentVersion, NewVersion: p.NewVersion, Phased: p.Phased}
 	}
 	client, err := grpcclient.New(cfg.ServerURL, cfg.TLS)
 	if err != nil {
 		log.Printf("post-apply report dial: %v", err)
-		return len(pkgs)
+		return updates.CountInstallable(pkgs)
 	}
 	defer client.Close()
 	if err := client.ReportUpdates(cfg.ServerID, cfg.AgentToken, list); err != nil {

internal/sync/sync.go

@@ -406,6 +406,7 @@ func runUpdateCheck(ctx context.Context, cfg *config.Config) {
 				Name:           p.Name,
 				CurrentVersion: p.CurrentVersion,
 				NewVersion:     p.NewVersion,
+				Phased:         p.Phased,
 			}
 		}
 		client, err := grpcclient.New(cfg.ServerURL, cfg.TLS)