feat: 品牌重命名 Sub2API -> TianShuAPI (基于官方 v0.1.46)

- 基于官方最新代码 upstream/main (93db889)
- 包含所有官方新功能：运维监控、促销码系统、Linux DO OAuth 等
- 仅修改品牌显示名称，保持所有功能完整
- 修改范围：前后端界面文字、i18n、邮件模板、日志输出

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/internal/service/auth_service.go

@@ -207,7 +207,7 @@ func (s *AuthService) SendVerifyCode(ctx context.Context, email string) error {
 	}
 
 	// 获取网站名称
-	siteName := "Sub2API"
+	siteName := "TianShuAPI"
 	if s.settingService != nil {
 		siteName = s.settingService.GetSiteName(ctx)
 	}
@@ -247,7 +247,7 @@ func (s *AuthService) SendVerifyCodeAsync(ctx context.Context, email string) (*S
 	}
 
 	// 获取网站名称
-	siteName := "Sub2API"
+	siteName := "TianShuAPI"
 	if s.settingService != nil {
 		siteName = s.settingService.GetSiteName(ctx)
 	}

backend/internal/service/setting_service.go

@@ -89,7 +89,7 @@ func (s *SettingService) GetPublicSettings(ctx context.Context) (*PublicSettings
 		EmailVerifyEnabled:  settings[SettingKeyEmailVerifyEnabled] == "true",
 		TurnstileEnabled:    settings[SettingKeyTurnstileEnabled] == "true",
 		TurnstileSiteKey:    settings[SettingKeyTurnstileSiteKey],
-		SiteName:            s.getStringOrDefault(settings, SettingKeySiteName, "Sub2API"),
+		SiteName:            s.getStringOrDefault(settings, SettingKeySiteName, "TianShuAPI"),
 		SiteLogo:            settings[SettingKeySiteLogo],
 		SiteSubtitle:        s.getStringOrDefault(settings, SettingKeySiteSubtitle, "Subscription to API Conversion Platform"),
 		APIBaseURL:          settings[SettingKeyAPIBaseURL],
@@ -247,7 +247,7 @@ func (s *SettingService) IsEmailVerifyEnabled(ctx context.Context) bool {
 func (s *SettingService) GetSiteName(ctx context.Context) string {
 	value, err := s.settingRepo.GetValue(ctx, SettingKeySiteName)
 	if err != nil || value == "" {
-		return "Sub2API"
+		return "TianShuAPI"
 	}
 	return value
 }
@@ -292,7 +292,7 @@ func (s *SettingService) InitializeDefaultSettings(ctx context.Context) error {
 	defaults := map[string]string{
 		SettingKeyRegistrationEnabled: "true",
 		SettingKeyEmailVerifyEnabled:  "false",
-		SettingKeySiteName:            "Sub2API",
+		SettingKeySiteName:            "TianShuAPI",
 		SettingKeySiteLogo:            "",
 		SettingKeyDefaultConcurrency:  strconv.Itoa(s.cfg.Default.UserConcurrency),
 		SettingKeyDefaultBalance:      strconv.FormatFloat(s.cfg.Default.UserBalance, 'f', 8, 64),
@@ -332,7 +332,7 @@ func (s *SettingService) parseSettings(settings map[string]string) *SystemSettin
 		TurnstileEnabled:             settings[SettingKeyTurnstileEnabled] == "true",
 		TurnstileSiteKey:             settings[SettingKeyTurnstileSiteKey],
 		TurnstileSecretKeyConfigured: settings[SettingKeyTurnstileSecretKey] != "",
-		SiteName:                     s.getStringOrDefault(settings, SettingKeySiteName, "Sub2API"),
+		SiteName:                     s.getStringOrDefault(settings, SettingKeySiteName, "TianShuAPI"),
 		SiteLogo:                     settings[SettingKeySiteLogo],
 		SiteSubtitle:                 s.getStringOrDefault(settings, SettingKeySiteSubtitle, "Subscription to API Conversion Platform"),
 		APIBaseURL:                   settings[SettingKeyAPIBaseURL],