v0.258.0: the last four Hungarian things an English household met

R-589 the update badge, R-590 the data-folder backup sentence, R-573 the two channel
banners, R-572 two dead helpers. All four were built in Go, which is why neither the
template parity fixtures nor TestI18nEnglishPages could see them; slice 5's LIVE proof
is what found them.

R-590 is the one that matters most: it is a promise about the customer's files. It
said, in Hungarian and under an already-English folder label, that a drop-zone is
temporary and unbacked. The test now asserts the CONSEQUENCE in both languages — and
that the two languages do not produce the same string, which would mean the English
fell back.

R-572 is not what its row said. The row claimed a template renders "vasárnap" on an
English page; measured, NO template and no Go file called pruneLabel or
nextPruneLabel. They were dead func-map entries returning Hungarian, so they are
deleted rather than translated — translating dead code would add machinery with no
reader and a test pinning a fiction. Deletion is fail-loud and that was proven: a
template naming the removed function panics loadTemplates at startup.

Five red-proofs. One of them says something about the gate rather than the code: the
Go-parity gate does not measure localeFuncs keys against the base capture, so the
citation to TestLocaleFuncsHungarianBundleMatchesFuncMap is what carries them — the
test was extended to make that citation true.

MinAgent: 0.131.0 (unchanged). Hungarian byte-identical.

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

controller/internal/web/alerts.go

@@ -102,9 +102,15 @@ func (am *AlertManager) SetHubPushStatus(fn func() HubPushStatusData) {
 }
 
 // SetAgentChannelAlert sets (down=true) or clears (down=false) the controller→agent channel-down
-// dashboard banner. Called by the channel-health checker each probe (idempotent). msg is the short
-// Hungarian display line.
-func (am *AlertManager) SetAgentChannelAlert(down bool, msg string) {
+// dashboard banner. Called by the channel-health checker each probe (idempotent).
+//
+// R-573 (v0.258.0): it takes the checker's CLASSIFIED REASON as a bundle key, not just the composed
+// sentence, so the banner follows the household's language like every other alert. `msg` stays as
+// the FAIL-OPEN fallback: `Alert.render` uses it verbatim when MessageKey is empty, so a reason
+// nobody mapped still shows the checker's Hungarian sentence rather than a blank banner or a raw
+// key. These two are the most operationally important banners there are — the 2026-07-25 outage
+// (R-77) was 17.5 hours long and this banner was the only signal.
+func (am *AlertManager) SetAgentChannelAlert(down bool, msgKey, msg string) {
 	am.mu.Lock()
 	defer am.mu.Unlock()
 	if !down {
@@ -114,7 +120,8 @@ func (am *AlertManager) SetAgentChannelAlert(down bool, msg string) {
 	am.agentChannelAlert = &Alert{
 		ID:          "agent-channel-down",
 		Level:       "error",
-		Message:     msg, // composed by the channel-health checker -- R-573
+		Message:     msg, // fail-open fallback when msgKey is empty -- R-573
+		MessageKey:  msgKey,
 		Link:        "/settings",
 		LinkTextKey: "alert.link.settings",
 	}
@@ -126,7 +133,7 @@ func (am *AlertManager) SetAgentChannelAlert(down bool, msg string) {
 // generic "agent unreachable" banner was the ONLY signal, and it looked like a dead agent. The two
 // can also be true at once — a drifted endpoint usually CAUSES the channel to be down — so folding
 // them together would hide the actionable one behind the symptom.
-func (am *AlertManager) SetEndpointDriftAlert(drift bool, msg string) {
+func (am *AlertManager) SetEndpointDriftAlert(drift bool, msgKey, msg string) {
 	am.mu.Lock()
 	defer am.mu.Unlock()
 	if !drift {
@@ -136,7 +143,8 @@ func (am *AlertManager) SetEndpointDriftAlert(drift bool, msg string) {
 	am.endpointDriftAlert = &Alert{
 		ID:          "local-api-endpoint-drift",
 		Level:       "error",
-		Message:     msg, // composed by the endpoint-drift checker -- R-573
+		Message:     msg, // fail-open fallback when msgKey is empty -- R-573
+		MessageKey:  msgKey,
 		Link:        "/settings",
 		LinkTextKey: "alert.link.settings",
 	}