v0.260.0 — a box ahead of the catalog reads „Naprakész", and the pin never moves backwards (R-524)

MEASURED 2026-09-15 (BIGNIGHT Phase 6): privatebin updated 2.0.5 -> 2.0.6, catalog
reverted to 2.0.5, and the box read „Frissítés elérhető — ma" over an Update that
would have moved the pin BACKWARDS onto a possibly-migrated datadir.

- stacks.CatalogOrder: the comparison gains a fourth answer (Ahead) and moves out of
  web, so the badge and UpdatePreflight cannot drift apart.
- The badge: ahead reads „Naprakész"/"Up to date", tag-ok, with a title saying why.
- The refusal: UpdatePreflight returns `downgrade` (409), born as a bundle key; the
  API now renders update refusals through errText so it reaches English households.
- Ahead is narrow: every differing service must be orderable AND newer, else Behind.
- Ordering is util.Version.Compare behind a tag normaliser — no second comparator.
- Three red-proofs, each seen to fail.

R-589 was already fixed in v0.258.0; only its register row was stale.

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

controller/internal/api/router.go

@@ -646,7 +646,13 @@ func (r *Router) actionStack(w http.ResponseWriter, req *http.Request, action, n
 			if ref.Reason == "not_found" {
 				status = http.StatusNotFound
 			}
-			writeJSON(w, status, apiResponse{OK: false, Error: ref.Message})
+			// errText, not ref.Message (v0.260.0): a refusal built with refuseUpdateErr carries its
+			// bundle key, so the household reads the refusal in its own language. A refusal still
+			// built from a Hungarian literal has no key and errText returns ref.Message byte for
+			// byte — which is why this line is safe to change for all of them at once, and why the
+			// R-524 downgrade refusal below is not a key nobody reads (the "seam built but never
+			// wired" class).
+			writeJSON(w, status, apiResponse{OK: false, Error: r.errText(req, ref)})
 			return
 		}
 	}