取消SMTP中继旧配置自动兼容

中继仅由enabled开关控制，不再根据旧字段自动启用或沿用旧开关状态。

backend/config/manager_v2.go

@@ -897,9 +897,6 @@ func applySectionPayload(current RuntimeConfig, section Section, payload json.Ra
 			return RuntimeConfig{}, ErrInvalidSecretChange
 		}
 		clearRelay = value.SMTPSectionConfig.Relay.Clear
-		if !value.SMTPSectionConfig.Relay.relayEnabledSet {
-			value.SMTPSectionConfig.Relay.RelayEnabled = current.SMTP.Relay.RelayEnabled
-		}
 		if clearRelay {
 			clearSMTPRelay(&value.SMTPSectionConfig.Relay)
 		} else {
@@ -933,9 +930,6 @@ func applySectionPayload(current RuntimeConfig, section Section, payload json.Ra
 			return RuntimeConfig{}, ErrInvalidSecretChange
 		}
 		clearRelay = value.MailSectionConfig.Relay.Clear
-		if !value.MailSectionConfig.Relay.relayEnabledSet {
-			value.MailSectionConfig.Relay.RelayEnabled = current.SMTP.Relay.RelayEnabled
-		}
 		if clearRelay {
 			clearSMTPRelay(&value.MailSectionConfig.Relay)
 		} else {
@@ -1017,7 +1011,6 @@ func clearSMTPRelay(relay *SMTPConfig) {
 	relay.From = ""
 	relay.FromDomain = ""
 	relay.Clear = false
-	relay.relayEnabledSet = true
 }
 
 func setCandidateGeneration(candidate *RuntimeConfig, generation uint64) {

backend/config/migrate.go

@@ -763,7 +763,6 @@ func validLegacyDatabasePassword(value string) bool {
 
 func legacySMTPConfig(root string, vault *credential.Vault, legacy legacyMigrationConfig) (SMTPConfig, []string, error) {
 	relay := SMTPConfig{
-		RelayEnabled:        legacy.SMTPHost != "" || legacy.SMTPPort != 0 || legacy.SMTPUsername != "" || legacy.SMTPFrom != "" || legacy.SMTPPassword != "",
 		RelayHost:           legacy.SMTPHost,
 		RelayPort:           legacy.SMTPPort,
 		Username:            legacy.SMTPUsername,

backend/config/model.go

@@ -1,9 +1,6 @@
 package config
 
-import (
-	"encoding/json"
-	"time"
-)
+import "time"
 
 type SetupState string
 
@@ -96,41 +93,6 @@ type SMTPConfig struct {
 	VerificationEnabled bool         `json:"verificationEnabled"`
 	LoginPolicy         string       `json:"loginPolicy"`
 	Clear               bool         `json:"clear,omitempty"`
-	relayEnabledSet     bool         `json:"-"`
-}
-
-func (s *SMTPConfig) UnmarshalJSON(data []byte) error {
-	type smtpConfigAlias SMTPConfig
-	var value smtpConfigAlias
-	if err := json.Unmarshal(data, &value); err != nil {
-		return err
-	}
-	var fields map[string]json.RawMessage
-	if err := json.Unmarshal(data, &fields); err != nil {
-		return err
-	}
-	*s = SMTPConfig(value)
-	_, enabledProvided := fields["enabled"]
-	configured := smtpRelayFieldsConfigured(*s)
-	s.relayEnabledSet = enabledProvided && (s.RelayEnabled || configured)
-	if !enabledProvided {
-		s.RelayEnabled = configured
-	}
-	return nil
-}
-
-func (s SMTPConfig) MarshalJSON() ([]byte, error) {
-	type smtpConfigAlias SMTPConfig
-	data, err := json.Marshal(smtpConfigAlias(s))
-	if err != nil || s.RelayEnabled || s.relayEnabledSet {
-		return data, err
-	}
-	var fields map[string]json.RawMessage
-	if err := json.Unmarshal(data, &fields); err != nil {
-		return nil, err
-	}
-	delete(fields, "enabled")
-	return json.Marshal(fields)
 }
 
 type EmailConfig struct {

backend/config/runtime_access.go

@@ -288,7 +288,6 @@ func CurrentSMTPRuntimeSettings() (SMTPRuntimeSettings, error) {
 		return SMTPRuntimeSettings{}, fmt.Errorf("runtime configuration is unavailable")
 	}
 	settings.Relay = SMTPConfig{
-		RelayEnabled:        cfg.SMTPHost != "" || cfg.SMTPPort != 0 || cfg.SMTPUsername != "" || cfg.SMTPFrom != "" || cfg.SMTPPassword != "",
 		RelayHost:           cfg.SMTPHost,
 		RelayPort:           cfg.SMTPPort,
 		Username:            cfg.SMTPUsername,

backend/config/validator.go

@@ -173,11 +173,11 @@ func smtpRelayFieldsConfigured(smtp SMTPConfig) bool {
 }
 
 func smtpRelayConfigured(smtp SMTPConfig) bool {
-	return smtpRelayFieldsConfigured(smtp) || smtp.RelayEnabled
+	return smtp.RelayEnabled
 }
 
 func smtpRelayEnabled(smtp SMTPConfig) bool {
-	return smtp.RelayEnabled || (!smtp.relayEnabledSet && smtpRelayFieldsConfigured(smtp))
+	return smtp.RelayEnabled
 }
 
 func (smtp SMTPConfig) RelayActive() bool {