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/homepage/icons/README.md

@@ -176,7 +176,7 @@ func (icon *Meta) Filenames(ref string) []string
 func NewURL(source Source, refOrName, format string) *URL
 
 // ErrInvalidIconURL is returned when icon URL parsing fails
-var ErrInvalidIconURL = gperr.New("invalid icon url")
+var ErrInvalidIconURL = errors.New("invalid icon url")
 ```
 
 ### Provider Interface

internal/homepage/icons/url.go

@@ -1,6 +1,7 @@
 package icons
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 
@@ -40,7 +41,7 @@ const (
 	VariantDark  Variant = "dark"
 )
 
-var ErrInvalidIconURL = gperr.New("invalid icon url")
+var ErrInvalidIconURL = errors.New("invalid icon url")
 
 func NewURL(source Source, refOrName, format string) *URL {
 	switch source {
@@ -119,7 +120,7 @@ func (u *URL) parse(v string, checkExists bool) error {
 	case "@target", "": // @target/favicon.ico, /favicon.ico
 		url := v[slashIndex:]
 		if url == "/" {
-			return ErrInvalidIconURL.Withf("%s", "empty path")
+			return fmt.Errorf("%w: empty path", ErrInvalidIconURL)
 		}
 		u.FullURL = &url
 		u.Source = SourceRelative
@@ -131,7 +132,7 @@ func (u *URL) parse(v string, checkExists bool) error {
 		}
 		parts := strings.Split(v[slashIndex+1:], ".")
 		if len(parts) != 2 {
-			return ErrInvalidIconURL.Withf("expect @%s/<reference>.<format>, e.g. @%s/adguard-home.webp", beforeSlash, beforeSlash)
+			return fmt.Errorf("%w: expect %s/<reference>.<format>, e.g. %s/adguard-home.webp", ErrInvalidIconURL, beforeSlash, beforeSlash)
 		}
 		reference, format := parts[0], strings.ToLower(parts[1])
 		if reference == "" || format == "" {
@@ -140,7 +141,7 @@ func (u *URL) parse(v string, checkExists bool) error {
 		switch format {
 		case "svg", "png", "webp":
 		default:
-			return ErrInvalidIconURL.Withf("%s", "invalid image format, expect svg/png/webp")
+			return fmt.Errorf("%w: invalid image format, expect svg/png/webp", ErrInvalidIconURL)
 		}
 		isLight, isDark := false, false
 		if strings.HasSuffix(reference, "-light") {
@@ -158,10 +159,10 @@ func (u *URL) parse(v string, checkExists bool) error {
 			IsDark:   isDark,
 		}
 		if checkExists && !u.HasIcon() {
-			return ErrInvalidIconURL.Withf("no such icon %s.%s from %s", reference, format, u.Source)
+			return fmt.Errorf("%w: no such icon %s.%s from %s", ErrInvalidIconURL, reference, format, u.Source)
 		}
 	default:
-		return ErrInvalidIconURL.Subject(v)
+		return gperr.PrependSubject(ErrInvalidIconURL, v)
 	}
 
 	return nil

internal/homepage/integrations/qbittorrent/client.go

@@ -2,13 +2,13 @@ package qbittorrent
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"net/http"
 	"net/url"
 
 	"github.com/bytedance/sonic"
 	"github.com/yusing/godoxy/internal/homepage/widgets"
-	gperr "github.com/yusing/goutils/errs"
 )
 
 type Client struct {
@@ -46,7 +46,7 @@ func (c *Client) doRequest(ctx context.Context, method, endpoint string, query u
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, gperr.Errorf("%w: %d %s", widgets.ErrHTTPStatus, resp.StatusCode, resp.Status)
+		return nil, fmt.Errorf("%w: %d %s", widgets.ErrHTTPStatus, resp.StatusCode, resp.Status)
 	}
 
 	return resp, nil

internal/homepage/widgets/README.md

@@ -50,8 +50,7 @@ const (
 ### Errors
 
 ```go
-var ErrInvalidProvider = gperr.New("invalid provider")
-var ErrHTTPStatus = gperr.New("http status")
+var ErrInvalidProvider = errors.New("invalid provider")
 ```
 
 ## API Reference

internal/homepage/widgets/http.go

@@ -1,14 +1,13 @@
 package widgets
 
 import (
+	"errors"
 	"net/http"
 	"time"
-
-	gperr "github.com/yusing/goutils/errs"
 )
 
 var HTTPClient = &http.Client{
 	Timeout: 10 * time.Second,
 }
 
-var ErrHTTPStatus = gperr.New("http status")
+var ErrHTTPStatus = errors.New("http status")

internal/homepage/widgets/widgets.go

@@ -2,6 +2,8 @@ package widgets
 
 import (
 	"context"
+	"errors"
+	"fmt"
 
 	"github.com/yusing/godoxy/internal/serialization"
 	gperr "github.com/yusing/goutils/errs"
@@ -30,21 +32,21 @@ var widgetProviders = map[string]struct{}{
 	WidgetProviderQbittorrent: {},
 }
 
-var ErrInvalidProvider = gperr.New("invalid provider")
+var ErrInvalidProvider = errors.New("invalid provider")
 
 func (cfg *Config) UnmarshalMap(m map[string]any) error {
 	var ok bool
 	cfg.Provider, ok = m["provider"].(string)
 	if !ok {
-		return ErrInvalidProvider.Withf("non string")
+		return fmt.Errorf("%w: non string", ErrInvalidProvider)
 	}
 	if _, ok := widgetProviders[cfg.Provider]; !ok {
-		return ErrInvalidProvider.Subject(cfg.Provider)
+		return gperr.PrependSubject(ErrInvalidProvider, cfg.Provider)
 	}
 	delete(m, "provider")
 	m, ok = m["config"].(map[string]any)
 	if !ok {
-		return gperr.New("invalid config")
+		return errors.New("invalid config")
 	}
 	return serialization.MapUnmarshalValidate(m, &cfg.Config)
 }