v0.247.0: i18n spike — the dashboard can speak English, Hungarian byte-identical

Message bundles (internal/i18n) expanded into templates before parsing, one
template set per language. Launcher, /backups, /apps/<slug> and the layout
converted; household language setting, POST /settings/language, ?lang= override,
report field. Parity test against fixtures captured from unconverted templates;
copy gates read templates expanded; new i18n_missing_gate.

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

controller/internal/web/handlers.go

@@ -314,6 +314,7 @@ func (s *Server) launcherApps() []LauncherApp {
 // "Indítópult megosztása" share state (v0.165.0) for the modal.
 func (s *Server) launcherHandler(w http.ResponseWriter, r *http.Request) {
 	data := s.baseData("launcher", "Indítópult")
+	data["TitleKey"] = "page.title.launcher" // i18n: the Hungarian title above is what hu renders
 	s.addRecoveryBanner(data, r) // R-241: the reminder bar, per visit
 	data["Apps"] = s.launcherApps()
 
@@ -934,6 +935,7 @@ func offboxWarningDisplay(lastWarning string, toggledCount int) string {
 // the status stat cards.
 func (s *Server) backupsHandler(w http.ResponseWriter, r *http.Request) {
 	data := s.backupsCommonData("backups", "Biztonsági mentés", r)
+	data["TitleKey"] = "page.title.backups" // i18n: the Hungarian title above is what hu renders
 
 	// System info for storage overview bars
 	data["SystemInfo"] = system.GetInfo(s.primaryHDDPath(), s.cpuCollector)