v0.238.0: the page follows the update, and a held app offers no way to start it (update arc slice 4 Part 4)

No behaviour change on the box — the surface only.

- Frissítés follows the job: the button shows the phase label (polling GET /api/stacks/{name}
  every 3 s) and the page reloads when updating goes false.
- An updating card offers no lifecycle button; a held card (failed update OR failed restore) shows
  the hold sentence with a Mentések link and nothing that would start it; a failed update that held
  nothing shows its sentence above the buttons. app_info shows the same three notices.
- The updating/held checks run BEFORE isOperational, which counts `restarting` as operational — how
  the 2026-09-01 spike saw a green Frissítés beside a crash loop. Pinned with StateRestarting
  fixtures; red-proofed by moving the checks after it (both tests fail).
- No new CSS, no version number.

Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/web/slice4_page_test.go

@@ -0,0 +1,70 @@
+package web
+
+import (
+	"strings"
+	"testing"
+
+	"gitea.dooplex.hu/admin/felhom-controller/internal/stacks"
+)
+
+// Slice 4 Part 4 — the card while an update runs, while an app is held, and after an update that
+// failed without a hold. Rendered through the REAL stacks template.
+//
+// THE TRAP THESE PIN: isOperationalState counts `restarting` as operational — that is how the
+// 2026-09-01 spike saw a green Frissítés beside a crash loop. Both fixtures below are in
+// StateRestarting on purpose, so a template that checked isOperational FIRST would render all three
+// lifecycle buttons and fail here.
+//
+// COMPANION RED-PROOF (REPORT.md): move the `{{if .Updating}}…{{else if .HoldReason}}` branches below
+// `isOperational` in stacks.html — the held and updating tests fail with the buttons present.
+
+var slice4LifecycleButtons = []string{
+	`stackAction(event, 'bookstack', 'update')`,
+	`stackAction(event, 'bookstack', 'restart')`,
+	`stackAction(event, 'bookstack', 'stop')`,
+	`stackAction(event, 'bookstack', 'start')`,
+}
+
+func TestSlice4_Page_UpdatingCardShowsThePhaseAndNoLifecycleButton(t *testing.T) {
+	st := ubStack(nil, map[string]string{"web": "nginx:1.27"}, "2026-07-18")
+	st.State = stacks.StateRestarting
+	st.Updating, st.UpdatePhase, st.UpdatePhaseLabel = true, stacks.UpdatePhasePulling, stacks.UpdatePhaseLabel(stacks.UpdatePhasePulling)
+	h := renderBackupPage(t, "stacks", ubStacksData(st))
+	if !strings.Contains(h, `data-update-phase="pulling"`) || !strings.Contains(h, stacks.UpdatePhaseLabel(stacks.UpdatePhasePulling)) {
+		t.Error("an updating card must show its phase label")
+	}
+	for _, b := range slice4LifecycleButtons {
+		if strings.Contains(h, b) {
+			t.Errorf("an updating card must offer no lifecycle button, found %q", b)
+		}
+	}
+}
+
+func TestSlice4_Page_HeldCardShowsTheHoldAndTheWayBack(t *testing.T) {
+	st := ubStack(nil, map[string]string{"web": "nginx:1.27"}, "2026-07-18")
+	st.State = stacks.StateRestarting
+	st.HoldReason = "A(z) bookstack frissítése 2026-09-13 10:00-kor nem sikerült — HOLD"
+	h := renderBackupPage(t, "stacks", ubStacksData(st))
+	if !strings.Contains(h, `data-held="true"`) || !strings.Contains(h, "HOLD") || !strings.Contains(h, `href="/backups/apps"`) {
+		t.Error("a held card must show the hold sentence and link Mentések")
+	}
+	for _, b := range slice4LifecycleButtons {
+		if strings.Contains(h, b) {
+			t.Errorf("a held card must offer nothing that starts or updates it, found %q", b)
+		}
+	}
+}
+
+func TestSlice4_Page_FailedUpdateWithoutHoldKeepsTheButtonsAndSaysWhy(t *testing.T) {
+	st := ubStack(nil, map[string]string{"web": "nginx:1.27"}, "2026-07-18")
+	st.UpdateError = stacks.MsgUpdatePullFailed
+	h := renderBackupPage(t, "stacks", ubStacksData(st))
+	if !strings.Contains(h, `data-update-error="true"`) || !strings.Contains(h, stacks.MsgUpdatePullFailed) {
+		t.Error("a failed update that held nothing must still say what happened")
+	}
+	for _, b := range slice4LifecycleButtons[:3] {
+		if !strings.Contains(h, b) {
+			t.Errorf("positive control: a running, unheld app keeps %q", b)
+		}
+	}
+}