v0.253.0 — errors carry the key of the sentence they are (R-557 slice 2 release B)

179 Hungarian sentences were built deep inside a package with fmt.Errorf and printed by
whoever caught them: too late to translate where they are shown, too early where they are
made. Every one now carries its key across that gap. ZERO Hungarian error literals remain.

util.MsgError does three things at once, each earned:
  - Error() is the Hungarian, byte for byte, so every un-converted printer is unchanged;
  - errors.Is answers for the kind AND for a wrapped cause (KindErrorf dropped the cause);
  - an error ARGUMENT renders recursively, so "formázás sikertelen: %w" translates whole.
A foreign error — restic, docker, ssh, the stdlib — prints verbatim. It is not ours.

76 display sites go through errText, and TestNoErrErrorInPageOutput convicts any that do
not. memoryVerdict returns an error rather than a sentence, so the deploy's 409 and the
household's language come from one value; UpdateRefusal gained a Cause to carry it.

Plurals, one rule, stated once: a key with .one/.other takes its COUNT first. Not a
per-call-site flag — the producer somebody forgot would read "3 app is not running". The
guard caught a real key collision (alert.deadapp.one) the day the rule landed.

TWO DEFECTS FOUND IN MY OWN TOOLING, recorded rather than quietly fixed. The bulk converter
silently dropped multi-line concatenations, damaging 7 producers — and the parity gate could
not see it, because every surviving fragment WAS a real base literal while the CALL had lost
text; two behaviour tests caught it. And the counting script was case-sensitive, so it said
"0 left" while five remained.

MinAgent: 0.131.0 (unchanged). No hub release needed.

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

controller/internal/stacks/update_test.go

@@ -20,22 +20,22 @@ import (
 var slice4T0 = time.Date(2026, 9, 13, 10, 0, 0, 0, time.UTC)
 
 type fakeGuards struct {
-	mu            sync.Mutex
-	calls         []string
-	held          bool
-	holdWhy       string
-	busy          bool
+	mu      sync.Mutex
+	calls   []string
+	held    bool
+	holdWhy string
+	busy    bool
 	// points are the copies the backup side holds, in tier order (R-475); pointsAfterBackup replaces
 	// them when BackupNow succeeds (nil = the backup changed nothing).
 	points            []UpdateRestorePoint
 	pointsAfterBackup []UpdateRestorePoint
 	cannotBackUp      bool
-	backupErr     error
-	dumpErr       error
-	holdErr       error
-	holdRP        UpdateRestorePoint
-	pinAtDump     string
-	stackDir      string
+	backupErr         error
+	dumpErr           error
+	holdErr           error
+	holdRP            UpdateRestorePoint
+	pinAtDump         string
+	stackDir          string
 }
 
 func (f *fakeGuards) note(c string) { f.mu.Lock(); f.calls = append(f.calls, c); f.mu.Unlock() }
@@ -129,7 +129,7 @@ func newSlice4Manager(t *testing.T) (*Manager, string, *fakeGuards, *composeRec)
 	m.updateGuards = g
 	m.updateComposeFn = c.fn
 	m.updateHealthFn = func(context.Context, string, time.Duration) (bool, string) { return true, "fake healthy" }
-	m.updateMemoryFn = func(int, int, int, int) (string, string) { return "", "" }
+	m.updateMemoryFn = func(int, int, int, int) (error, string) { return nil, "" }
 	m.updateDiskFreeFn = func() (float64, bool) { return 50, true }
 	m.updateNowFn = func() time.Time { return slice4T0 } // R-457: the SAME clock the age check reads
 	m.execFn = func(string, ...string) (string, error) { return "", nil }
@@ -338,8 +338,8 @@ func TestSlice4_D_CheapRefusals(t *testing.T) {
 			if err := os.WriteFile(filepath.Join(catDir, ".felhom.yml"), []byte("resources:\n  mem_request: 900M\n"), 0o644); err != nil {
 				panic(err)
 			}
-			m.updateMemoryFn = func(newReq, _, _, _ int) (string, string) {
-				return fmt.Sprintf("Nincs elég memória (%d MB)", newReq), ""
+			m.updateMemoryFn = func(newReq, _, _, _ int) (error, string) {
+				return fmt.Errorf("Nincs elég memória (%d MB)", newReq), ""
 			}
 		}, "memory", "Nincs elég memória (900 MB)"},
 		{"disk", func(m *Manager, _ *fakeGuards, _ string) {