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

apt lists phased updates as upgradable while an upgrade defers them until
Ubuntu selects the host, so a freshly patched server kept reporting pending
updates. The agent now flags them; the server stores the flag and leaves them
out of patch run counts, and the server page shows them in their own section.

server/internal/services/patch_runs.go

@@ -83,7 +83,7 @@ func serverBootTime(ctx context.Context, instanceID, serverID string) *time.Time
 }
 
 func newServerRun(s models.Server, now time.Time) models.PatchServerRun {
-	r := models.PatchServerRun{ServerID: s.ServerID, Hostname: s.Hostname, Status: models.PatchSrvQueued, PendingBefore: len(s.AvailableUpdates)}
+	r := models.PatchServerRun{ServerID: s.ServerID, Hostname: s.Hostname, Status: models.PatchSrvQueued, PendingBefore: InstallableUpdateCount(s.AvailableUpdates)}
 	if !patchrun.AgentSupportsPatchResults(s.AgentVersion) {
 		v := s.AgentVersion
 		if v == "" {

server/internal/services/updates_count.go

@@ -0,0 +1,17 @@
+package services
+
+import "gitea.hostxtra.co.uk/mrhid6/vantage/server/internal/models"
+
+// InstallableUpdateCount is the number of pending updates an upgrade would
+// install now. Ubuntu phased updates are listed by apt but deferred until the
+// host's phase comes up, so they are not counted: counting them made a patch
+// run look as if it installed less than it did.
+func InstallableUpdateCount(ups []models.PackageUpdate) int {
+	n := 0
+	for _, u := range ups {
+		if !u.Phased {
+			n++
+		}
+	}
+	return n
+}

server/internal/services/updates_count_test.go

@@ -0,0 +1,23 @@
+package services
+
+import (
+	"testing"
+
+	"gitea.hostxtra.co.uk/mrhid6/vantage/server/internal/models"
+)
+
+// Phased updates are listed but not installable yet, so they never count as
+// pending: they must not lower "updates installed" on a patch run.
+func TestInstallableUpdateCount(t *testing.T) {
+	ups := []models.PackageUpdate{
+		{Name: "curl"},
+		{Name: "netplan.io", Phased: true},
+		{Name: "openssl"},
+	}
+	if got := InstallableUpdateCount(ups); got != 2 {
+		t.Fatalf("got %d, want 2", got)
+	}
+	if got := InstallableUpdateCount(nil); got != 0 {
+		t.Fatalf("got %d for nil, want 0", got)
+	}
+}