docs: add comments for all functions

util/common/err.go

@@ -1,3 +1,4 @@
+// Package common provides common utility functions for error handling, formatting, and multi-error management.
 package common
 
 import (
@@ -7,16 +8,19 @@ import (
 	"github.com/mhsanaei/3x-ui/v2/logger"
 )
 
+// NewErrorf creates a new error with formatted message.
 func NewErrorf(format string, a ...any) error {
 	msg := fmt.Sprintf(format, a...)
 	return errors.New(msg)
 }
 
+// NewError creates a new error from the given arguments.
 func NewError(a ...any) error {
 	msg := fmt.Sprintln(a...)
 	return errors.New(msg)
 }
 
+// Recover handles panic recovery and logs the panic error if a message is provided.
 func Recover(msg string) any {
 	panicErr := recover()
 	if panicErr != nil {