refactor(10.2-01): nest framework packages under modules

- Move remaining beach packages and embedded admin assets\n- Rewrite framework, example, build, and gate paths

modules/cabana/lang.go

@@ -0,0 +1,24 @@
+package cabana
+
+import (
+	"net/http"
+)
+
+// adminLangPrefix is the only namespace the public bundle serves (D-20).
+const adminLangPrefix = "backend::lang."
+
+// langBundle serves GET {prefix}/api/v1/lang: every backend::lang key as CLDR
+// forms for the request locale, with the fallback locale's keys underneath.
+// It is public (the login screen needs it) and never includes another
+// namespace.
+func (s *service) langBundle(w http.ResponseWriter, r *http.Request) {
+	tr := s.translator()
+	locale := schemaLocale(r.Context(), tr)
+	data := map[string]map[string]string{}
+	if tr != nil {
+		locale = tr.Resolved(locale, adminLangPrefix)
+		data = tr.Bundle(locale, adminLangPrefix)
+	}
+	w.Header().Set("Cache-Control", "no-cache")
+	WriteData(w, http.StatusOK, data, map[string]any{"locale": locale})
+}