Add i18n support with English and Spanish translations

- Created i18n package with translator and middleware
- Added translation files for English (en.json) and Spanish (es.json)
- Updated all HTTP handlers to use i18n for error/success messages
- Added comprehensive test coverage for i18n (87%)
- Updated CI workflow to use Go 1.24
- All tests passing with 50.8% total coverage

internal/infrastructure/http/user_handlers.go

@@ -4,16 +4,19 @@ import (
 	"net/http"
 
 	"apocapoc-api/internal/application/commands"
+	"apocapoc-api/internal/i18n"
 	"apocapoc-api/internal/shared/errors"
 )
 
 type UserHandlers struct {
 	deleteUserHandler *commands.DeleteUserHandler
+	translator        *i18n.Translator
 }
 
-func NewUserHandlers(deleteUserHandler *commands.DeleteUserHandler) *UserHandlers {
+func NewUserHandlers(deleteUserHandler *commands.DeleteUserHandler, translator *i18n.Translator) *UserHandlers {
 	return &UserHandlers{
 		deleteUserHandler: deleteUserHandler,
+		translator:        translator,
 	}
 }
 
@@ -38,14 +41,15 @@ func (h *UserHandlers) DeleteAccount(w http.ResponseWriter, r *http.Request) {
 	err := h.deleteUserHandler.Handle(r.Context(), cmd)
 	if err != nil {
 		if err == errors.ErrNotFound {
-			respondError(w, http.StatusNotFound, "User not found")
+			respondErrorI18n(w, r, h.translator, http.StatusNotFound, "user_not_found")
 			return
 		}
-		respondError(w, http.StatusInternalServerError, "Failed to delete account")
+		respondErrorI18n(w, r, h.translator, http.StatusInternalServerError, "failed_delete_user")
 		return
 	}
 
+	lang := i18n.GetLanguageFromContext(r.Context())
 	respondJSON(w, http.StatusOK, map[string]string{
-		"message": "Account deleted successfully",
+		"message": h.translator.Success(lang, "user_deleted"),
 	})
 }