feat: add precise diagnostics and optional client copy logging controls

logx/logx.go

@@ -22,6 +22,7 @@ import (
 // standard stream. File takes precedence over Output and appends to the named
 // file.
 type Config struct {
+	TimeZone    string         `json:"timeZone"` // Empty retains existing timestamp behavior.
 	Level       string         `json:"level"`
 	Format      string         `json:"format"`
 	Output      string         `json:"output"`
@@ -73,7 +74,8 @@ func init() {
 // call Close when the process is shutting down.
 func New(cfg Config) (*Logger, error) {
 	cfg = normalizeConfig(cfg)
-	if err := cfg.Validate(); err != nil {
+	location, err := cfg.validate()
+	if err != nil {
 		return nil, err
 	}
 	level, err := parseLevel(cfg.Level)
@@ -95,6 +97,9 @@ func New(cfg Config) (*Logger, error) {
 	} else {
 		handler = slog.NewJSONHandler(writer, opts)
 	}
+	if location != nil {
+		handler = zoneHandler{Handler: handler, location: location}
+	}
 	logger := slog.New(handler)
 	if cfg.Service != "" {
 		logger = logger.With("service", cfg.Service)