Add rules language support and improve password validation across the app

rules.go

@@ -90,9 +90,20 @@ func getRules(lang string) []Rule {
 
 func registerRuleRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("GET /api/rules", requireAuth(handleListRules))
+	mux.HandleFunc("GET /api/rules/languages", requireAuth(handleListRuleLanguages))
 	mux.HandleFunc("POST /api/rules/reload", requireAdmin(handleReloadRules))
 }
 
+func handleListRuleLanguages(w http.ResponseWriter, r *http.Request) {
+	rulesMu.RLock()
+	defer rulesMu.RUnlock()
+	out := make([]string, 0, len(rules))
+	for lang := range rules {
+		out = append(out, lang)
+	}
+	writeJSON(w, http.StatusOK, out)
+}
+
 func handleListRules(w http.ResponseWriter, r *http.Request) {
 	lang := r.URL.Query().Get("lang")
 	if lang == "" {