fix(frontend): sync with main and finalize i18n & component optimizations

backend/internal/pkg/errors/types.go

+// Package errors provides application error types and helpers.
 // nolint:mnd
 package errors
 

backend/internal/pkg/googleapi/status.go

+// Package googleapi provides helpers for Google-style API responses.
 package googleapi
 
 import "net/http"