refactor(errs): migrate from gperr.Error to standard Go error interface

This is a large-scale refactoring across the codebase that replaces the custom
`gperr.Error` type with Go's standard `error` interface. The changes include:

- Replacing `gperr.Error` return types with `error` in function signatures
- Using `errors.New()` and `fmt.Errorf()` instead of `gperr.New()` and `gperr.Errorf()`
- Using `%w` format verb for error wrapping instead of `.With()` method
- Replacing `gperr.Subject()` calls with `gperr.PrependSubject()`
- Converting error logging from `gperr.Log*()` functions to zerolog's `.Err().Msg()` pattern
- Update NewLogger to handle multiline error message
- Updating `goutils` submodule to latest commit

This refactoring aligns with Go idioms and removes the dependency on
custom error handling abstractions in favor of standard library patterns.

internal/net/gphttp/middleware/errorpage/error_page.go

@@ -11,7 +11,6 @@ import (
 	"github.com/yusing/godoxy/internal/common"
 	"github.com/yusing/godoxy/internal/watcher"
 	"github.com/yusing/godoxy/internal/watcher/events"
-	gperr "github.com/yusing/goutils/errs"
 	"github.com/yusing/goutils/fs"
 	"github.com/yusing/goutils/task"
 )
@@ -93,7 +92,7 @@ func watchDir() {
 				loadContent()
 			}
 		case err := <-errCh:
-			gperr.LogError("error watching error page directory", err)
+			log.Err(err).Msg("error watching error page directory")
 		}
 	}
 }