R-553: four decisions stop reading their own Hungarian words (sites 1-4)

Every Hungarian sentence is byte-identical; each decision now reads a signal set where the message is
made. util.KindErrorf builds the same bytes fmt.Errorf did while carrying a sentinel for errors.Is.

- Deploy status (api/router.go): deployStatusFor() by kind — stacks.ErrAlreadyDeployed (409),
  ErrRequiredField / ErrPathMissing / ErrNotEnoughMemory (400). The „kötelező" / „memória" /
  "does not exist" / "already deployed" text chain is gone.
- Off-site failure class (backup/offbox.go): ErrOffsiteQuota replaces the „tárhelykeretet" match. The
  restic/ssh signatures stay text matches on purpose — that output is not ours and is not translated.
- Alert placement (web/alerts.go): monitor.HealthReport carries WarningKinds parallel to Warnings;
  the "not on a separate drive" warning is inline by KIND. The hub report is untouched (builder.go
  copies Status/Issues/Warnings only) — pinned by a wire test.
- Stale off-site note (web/handlers.go): settings LastWarningKind + backup.OffboxWarnNoAppsSelected.
  The text test survives ONLY for kind == "" (a box whose last run predates 0.251.0) and is removed
  when R-570 closes; slice 2 must not translate that producer before then.

Tests (all red-proofed by restoring the pre-fix predicate — see the audit's redproofs.txt):
TestR553_Deploy_DecisionSurvivesWordingChange, TestR553_DeployHandlerUsesTheKind,
TestR553_DeployProducersCarryKindAndKeepTheirWords (through the real DeployStack),
TestR553_OffsiteQuota_{Decision,HeadLine}SurvivesWordingChange, TestR553_OffboxRunRecordsTheKind,
TestR553_StorageWarningsCarryKindsAndKeepTheirWords, TestR553_DiskWarningPlacementSurvivesWordingChange,
TestR553_HubReportWarningsAreUnchangedOnTheWire, TestR553_StaleNote*, TestR553_WarningKindIsPersistedAndCopied.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/web/handlers.go

@@ -897,7 +897,7 @@ func (s *Server) backupsOffboxData(data map[string]interface{}) {
 	data["OffboxToggledCount"] = offboxToggled
 	// Part E (v0.126.0): the LastWarning DISPLAY pick — never a state mutation.
 	if offboxTgt != nil {
-		data["OffboxWarningDisplay"] = offboxWarningDisplay(offboxTgt.LastWarning, offboxToggled)
+		data["OffboxWarningDisplay"] = offboxWarningDisplay(offboxTgt.LastWarning, offboxTgt.LastWarningKind, offboxToggled)
 	} else {
 		data["OffboxWarningDisplay"] = ""
 	}
@@ -913,9 +913,9 @@ func (s *Server) backupsOffboxData(data map[string]interface{}) {
 	data["OffboxBlockedSet"] = blocked
 }
 
-// offboxStaleWarningMarker is the substring the zero-toggled offbox run writes into
-// LastWarning (backup/offbox.go); offboxSelectionChangedLine replaces it once the
-// selection has moved on.
+// offboxStaleWarningMarker is the substring the zero-toggled offbox run wrote into LastWarning before
+// v0.251.0, when the run started recording a KIND beside it (R-553). It is kept ONLY to read boxes
+// upgraded with that older text already persisted — see offboxWarningDisplay.
 const (
 	offboxStaleWarningMarker   = "nincs mentésre jelölt alkalmazás"
 	offboxSelectionChangedLine = "A kijelölés módosult az utolsó futás óta — a következő távoli mentés már tartalmazza."
@@ -927,8 +927,21 @@ const (
 // replace it with the honest "selection changed, the next run covers it" note.
 // Pure display logic: the persisted LastWarning is never touched, and every other
 // warning (quota, partial failure) passes through verbatim.
-func offboxWarningDisplay(lastWarning string, toggledCount int) string {
-	if toggledCount >= 1 && strings.Contains(lastWarning, offboxStaleWarningMarker) {
+// R-553 — the decision is made on the KIND the run recorded, not on the words of the sentence.
+// The one text test that remains runs ONLY when there is no kind, i.e. on a box whose last off-site
+// run happened before v0.251.0 and whose persisted warning therefore predates kinds.
+//
+// R-553 legacy: remove after every fleet box has completed one off-site run on ≥ 0.251.0 (row R-570).
+// Localisation slice 2 (R-557) must not translate the producer at backup/offbox.go until that row is
+// closed — translating it while this fallback is still needed would strand exactly those boxes.
+func offboxWarningDisplay(lastWarning, kind string, toggledCount int) string {
+	if toggledCount < 1 {
+		return lastWarning
+	}
+	if kind == backup.OffboxWarnNoAppsSelected {
+		return offboxSelectionChangedLine
+	}
+	if kind == "" && strings.Contains(lastWarning, offboxStaleWarningMarker) {
 		return offboxSelectionChangedLine
 	}
 	return lastWarning