refactor(serialization): generalize unmarshal/load functions with pluggable format handlers

Replace YAML-specific functions with generic ones accepting unmarshaler/marshaler
function parameters. This enables future support for JSON and other formats
while maintaining current YAML behavior.

- UnmarshalValidateYAML -> UnmarshalValidate(unmarshalFunc)
- UnmarshalValidateYAMLXSync -> UnmarshalValidateXSync(unmarshalFunc)
- SaveJSON -> SaveFile(marshalFunc)
- LoadJSONIfExist -> LoadFileIfExist(unmarshalFunc)
- Add UnmarshalValidateReader for reader-based decoding

Testing: all 12 staged test files updated to use new API

internal/autocert/config_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/goccy/go-yaml"
 	"github.com/stretchr/testify/require"
 	"github.com/yusing/godoxy/internal/autocert"
 	"github.com/yusing/godoxy/internal/dnsproviders"
@@ -25,9 +26,9 @@ func TestEABConfigRequired(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			yaml := fmt.Appendf(nil, "eab_kid: %s\neab_hmac: %s", test.cfg.EABKid, test.cfg.EABHmac)
+			yamlCfg := fmt.Appendf(nil, "eab_kid: %s\neab_hmac: %s", test.cfg.EABKid, test.cfg.EABHmac)
 			cfg := autocert.Config{}
-			err := serialization.UnmarshalValidateYAML(yaml, &cfg)
+			err := serialization.UnmarshalValidate(yamlCfg, &cfg, yaml.Unmarshal)
 			if (err != nil) != test.wantErr {
 				t.Errorf("Validate() error = %v, wantErr %v", err, test.wantErr)
 			}

internal/autocert/provider_test/multi_cert_test.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"testing"
 
+	"github.com/goccy/go-yaml"
 	"github.com/stretchr/testify/require"
 	"github.com/yusing/godoxy/internal/autocert"
 	"github.com/yusing/godoxy/internal/serialization"
@@ -41,7 +42,7 @@ func TestMultipleCertificatesLifecycle(t *testing.T) {
 	cfg.HTTPClient = acmeServer.httpClient()
 
 	/* unmarshal yaml config with multiple certs */
-	err := error(serialization.UnmarshalValidateYAML(yamlConfig, &cfg))
+	err := error(serialization.UnmarshalValidate(yamlConfig, &cfg, yaml.Unmarshal))
 	require.NoError(t, err)
 	require.Equal(t, []string{"main.example.com"}, cfg.Domains)
 	require.Len(t, cfg.Extra, 2)

internal/autocert/setup_test.go

@@ -3,6 +3,7 @@ package autocert_test
 import (
 	"testing"
 
+	"github.com/goccy/go-yaml"
 	"github.com/stretchr/testify/require"
 	"github.com/yusing/godoxy/internal/autocert"
 	"github.com/yusing/godoxy/internal/dnsproviders"
@@ -42,7 +43,7 @@ extra:
 `
 
 	var cfg autocert.Config
-	err := error(serialization.UnmarshalValidateYAML([]byte(cfgYAML), &cfg))
+	err := error(serialization.UnmarshalValidate([]byte(cfgYAML), &cfg, yaml.Unmarshal))
 	require.NoError(t, err)
 
 	// Test: extra[0] inherits all fields from main except CertPath and KeyPath.