R-898: ring 0 stages exactly the told kernel (select listed, KernelSet(kver))

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

internal/osupdate/kernel_test.go

@@ -54,8 +54,12 @@ func TestKernel_Ring0ToldNightStagesThenReboots(t *testing.T) {
 			ap = x
 		}
 	}
-	if ap["select"] != "pending-kernel" || ap["expect_kver"] != kNew || ap["lane"] != "slow" {
-		t.Fatalf("stage plan = %v", ap)
+	// R-898: EXACTLY the told kernel — the listed set derived from it, never "pending" (red before the fix: select was
+	// pending-kernel, so a newer kernel in the sources by night was refused R23 and the night was lost)
+	pk, _ := json.Marshal(ap["packages"])
+	if ap["select"] != "listed" || ap["expect_kver"] != kNew || ap["lane"] != "slow" ||
+		string(pk) != `[{"name":"proxmox-kernel-7.0","origin":"Proxmox Debian Repository","version":"7.0.14-22"},{"name":"proxmox-kernel-7.0.14-22-pve-signed","origin":"Proxmox Debian Repository","version":"7.0.14-22"}]` {
+		t.Fatalf("stage plan = %v (packages %s)", ap, pk)
 	}
 	if p.Kernel.Outcome != "staged" || !p.Kernel.Healthy {
 		t.Fatalf("kernel report = %+v", p.Kernel)
@@ -312,3 +316,13 @@ func TestKernel_KeptStageReportIsStaged(t *testing.T) {
 		t.Fatalf("kept = %+v", rep)
 	}
 }
+
+func TestKernelSet(t *testing.T) {
+	if got := KernelSet("7.0.14-20-pve"); len(got) != 2 || got[0].Name != "proxmox-kernel-7.0" || got[0].Version != "7.0.14-20" ||
+		got[1].Name != "proxmox-kernel-7.0.14-20-pve-signed" {
+		t.Fatalf("%+v", got)
+	}
+	if KernelSet("7.0; reboot") != nil || KernelSet("") != nil {
+		t.Fatal("a non-kernel string must give no set")
+	}
+}