fix(lint): 修复所有 Go 命名规范问题

- 全局替换 ApiKey → APIKey（类型、字段、方法、变量）
- 修复所有 initialism 命名（API, SMTP, HTML, URL 等）
- 添加所有缺失的包注释
- 修复导出符号的注释格式

主要修改：
- ApiKey → APIKey（所有出现的地方）
- ApiKeyID → APIKeyID
- ApiKeyIDs → APIKeyIDs
- TestSmtpConnection → TestSMTPConnection
- HtmlURL → HTMLURL
- 添加 20+ 个包注释
- 修复 10+ 个导出符号注释格式

验证结果：
- ✓ golangci-lint: 0 issues
- ✓ 单元测试: 通过
- ✓ 集成测试: 通过

backend/internal/handler/admin/account_handler.go

@@ -1,3 +1,4 @@
+// Package admin provides HTTP handlers for administrative operations.
 package admin
 
 import (

backend/internal/handler/admin/dashboard_handler.go

@@ -75,8 +75,8 @@ func (h *DashboardHandler) GetStats(c *gin.Context) {
 		"active_users":    stats.ActiveUsers,
 
 		// API Key 统计
-		"total_api_keys":  stats.TotalApiKeys,
-		"active_api_keys": stats.ActiveApiKeys,
+		"total_api_keys":  stats.TotalAPIKeys,
+		"active_api_keys": stats.ActiveAPIKeys,
 
 		// 账户统计
 		"total_accounts":     stats.TotalAccounts,
@@ -193,10 +193,10 @@ func (h *DashboardHandler) GetModelStats(c *gin.Context) {
 	})
 }
 
-// GetApiKeyUsageTrend handles getting API key usage trend data
+// GetAPIKeyUsageTrend handles getting API key usage trend data
 // GET /api/v1/admin/dashboard/api-keys-trend
 // Query params: start_date, end_date (YYYY-MM-DD), granularity (day/hour), limit (default 5)
-func (h *DashboardHandler) GetApiKeyUsageTrend(c *gin.Context) {
+func (h *DashboardHandler) GetAPIKeyUsageTrend(c *gin.Context) {
 	startTime, endTime := parseTimeRange(c)
 	granularity := c.DefaultQuery("granularity", "day")
 	limitStr := c.DefaultQuery("limit", "5")
@@ -205,7 +205,7 @@ func (h *DashboardHandler) GetApiKeyUsageTrend(c *gin.Context) {
 		limit = 5
 	}
 
-	trend, err := h.dashboardService.GetApiKeyUsageTrend(c.Request.Context(), startTime, endTime, granularity, limit)
+	trend, err := h.dashboardService.GetAPIKeyUsageTrend(c.Request.Context(), startTime, endTime, granularity, limit)
 	if err != nil {
 		response.Error(c, 500, "Failed to get API key usage trend")
 		return
@@ -273,26 +273,26 @@ func (h *DashboardHandler) GetBatchUsersUsage(c *gin.Context) {
 	response.Success(c, gin.H{"stats": stats})
 }
 
-// BatchApiKeysUsageRequest represents the request body for batch api key usage stats
-type BatchApiKeysUsageRequest struct {
-	ApiKeyIDs []int64 `json:"api_key_ids" binding:"required"`
+// BatchAPIKeysUsageRequest represents the request body for batch api key usage stats
+type BatchAPIKeysUsageRequest struct {
+	APIKeyIDs []int64 `json:"api_key_ids" binding:"required"`
 }
 
-// GetBatchApiKeysUsage handles getting usage stats for multiple API keys
+// GetBatchAPIKeysUsage handles getting usage stats for multiple API keys
 // POST /api/v1/admin/dashboard/api-keys-usage
-func (h *DashboardHandler) GetBatchApiKeysUsage(c *gin.Context) {
-	var req BatchApiKeysUsageRequest
+func (h *DashboardHandler) GetBatchAPIKeysUsage(c *gin.Context) {
+	var req BatchAPIKeysUsageRequest
 	if err := c.ShouldBindJSON(&req); err != nil {
 		response.BadRequest(c, "Invalid request: "+err.Error())
 		return
 	}
 
-	if len(req.ApiKeyIDs) == 0 {
+	if len(req.APIKeyIDs) == 0 {
 		response.Success(c, gin.H{"stats": map[string]any{}})
 		return
 	}
 
-	stats, err := h.dashboardService.GetBatchApiKeyUsageStats(c.Request.Context(), req.ApiKeyIDs)
+	stats, err := h.dashboardService.GetBatchAPIKeyUsageStats(c.Request.Context(), req.APIKeyIDs)
 	if err != nil {
 		response.Error(c, 500, "Failed to get API key usage stats")
 		return

backend/internal/handler/admin/gemini_oauth_handler.go

@@ -18,6 +18,7 @@ func NewGeminiOAuthHandler(geminiOAuthService *service.GeminiOAuthService) *Gemi
 	return &GeminiOAuthHandler{geminiOAuthService: geminiOAuthService}
 }
 
+// GetCapabilities returns the Gemini OAuth configuration capabilities.
 // GET /api/v1/admin/gemini/oauth/capabilities
 func (h *GeminiOAuthHandler) GetCapabilities(c *gin.Context) {
 	cfg := h.geminiOAuthService.GetOAuthConfig()

backend/internal/handler/admin/group_handler.go

@@ -237,9 +237,9 @@ func (h *GroupHandler) GetGroupAPIKeys(c *gin.Context) {
 		return
 	}
 
-	outKeys := make([]dto.ApiKey, 0, len(keys))
+	outKeys := make([]dto.APIKey, 0, len(keys))
 	for i := range keys {
-		outKeys = append(outKeys, *dto.ApiKeyFromService(&keys[i]))
+		outKeys = append(outKeys, *dto.APIKeyFromService(&keys[i]))
 	}
 	response.Paginated(c, outKeys, total, page, pageSize)
 }

backend/internal/handler/admin/setting_handler.go

@@ -230,9 +230,9 @@ type TestSMTPRequest struct {
 	SMTPUseTLS   bool   `json:"smtp_use_tls"`
 }
 
-// TestSmtpConnection 测试SMTP连接
+// TestSMTPConnection 测试SMTP连接
 // POST /api/v1/admin/settings/test-smtp
-func (h *SettingHandler) TestSmtpConnection(c *gin.Context) {
+func (h *SettingHandler) TestSMTPConnection(c *gin.Context) {
 	var req TestSMTPRequest
 	if err := c.ShouldBindJSON(&req); err != nil {
 		response.BadRequest(c, "Invalid request: "+err.Error())
@@ -246,13 +246,13 @@ func (h *SettingHandler) TestSmtpConnection(c *gin.Context) {
 	// 如果未提供密码，从数据库获取已保存的密码
 	password := req.SMTPPassword
 	if password == "" {
-		savedConfig, err := h.emailService.GetSmtpConfig(c.Request.Context())
+		savedConfig, err := h.emailService.GetSMTPConfig(c.Request.Context())
 		if err == nil && savedConfig != nil {
 			password = savedConfig.Password
 		}
 	}
 
-	config := &service.SmtpConfig{
+	config := &service.SMTPConfig{
 		Host:     req.SMTPHost,
 		Port:     req.SMTPPort,
 		Username: req.SMTPUsername,
@@ -260,7 +260,7 @@ func (h *SettingHandler) TestSmtpConnection(c *gin.Context) {
 		UseTLS:   req.SMTPUseTLS,
 	}
 
-	err := h.emailService.TestSmtpConnectionWithConfig(config)
+	err := h.emailService.TestSMTPConnectionWithConfig(config)
 	if err != nil {
 		response.ErrorFrom(c, err)
 		return
@@ -297,13 +297,13 @@ func (h *SettingHandler) SendTestEmail(c *gin.Context) {
 	// 如果未提供密码，从数据库获取已保存的密码
 	password := req.SMTPPassword
 	if password == "" {
-		savedConfig, err := h.emailService.GetSmtpConfig(c.Request.Context())
+		savedConfig, err := h.emailService.GetSMTPConfig(c.Request.Context())
 		if err == nil && savedConfig != nil {
 			password = savedConfig.Password
 		}
 	}
 
-	config := &service.SmtpConfig{
+	config := &service.SMTPConfig{
 		Host:     req.SMTPHost,
 		Port:     req.SMTPPort,
 		Username: req.SMTPUsername,
@@ -355,10 +355,10 @@ func (h *SettingHandler) SendTestEmail(c *gin.Context) {
 	response.Success(c, gin.H{"message": "Test email sent successfully"})
 }
 
-// GetAdminApiKey 获取管理员 API Key 状态
+// GetAdminAPIKey 获取管理员 API Key 状态
 // GET /api/v1/admin/settings/admin-api-key
-func (h *SettingHandler) GetAdminApiKey(c *gin.Context) {
-	maskedKey, exists, err := h.settingService.GetAdminApiKeyStatus(c.Request.Context())
+func (h *SettingHandler) GetAdminAPIKey(c *gin.Context) {
+	maskedKey, exists, err := h.settingService.GetAdminAPIKeyStatus(c.Request.Context())
 	if err != nil {
 		response.ErrorFrom(c, err)
 		return
@@ -370,10 +370,10 @@ func (h *SettingHandler) GetAdminApiKey(c *gin.Context) {
 	})
 }
 
-// RegenerateAdminApiKey 生成/重新生成管理员 API Key
+// RegenerateAdminAPIKey 生成/重新生成管理员 API Key
 // POST /api/v1/admin/settings/admin-api-key/regenerate
-func (h *SettingHandler) RegenerateAdminApiKey(c *gin.Context) {
-	key, err := h.settingService.GenerateAdminApiKey(c.Request.Context())
+func (h *SettingHandler) RegenerateAdminAPIKey(c *gin.Context) {
+	key, err := h.settingService.GenerateAdminAPIKey(c.Request.Context())
 	if err != nil {
 		response.ErrorFrom(c, err)
 		return
@@ -384,10 +384,10 @@ func (h *SettingHandler) RegenerateAdminApiKey(c *gin.Context) {
 	})
 }
 
-// DeleteAdminApiKey 删除管理员 API Key
+// DeleteAdminAPIKey 删除管理员 API Key
 // DELETE /api/v1/admin/settings/admin-api-key
-func (h *SettingHandler) DeleteAdminApiKey(c *gin.Context) {
-	if err := h.settingService.DeleteAdminApiKey(c.Request.Context()); err != nil {
+func (h *SettingHandler) DeleteAdminAPIKey(c *gin.Context) {
+	if err := h.settingService.DeleteAdminAPIKey(c.Request.Context()); err != nil {
 		response.ErrorFrom(c, err)
 		return
 	}

backend/internal/handler/admin/usage_handler.go

@@ -17,14 +17,14 @@ import (
 // UsageHandler handles admin usage-related requests
 type UsageHandler struct {
 	usageService  *service.UsageService
-	apiKeyService *service.ApiKeyService
+	apiKeyService *service.APIKeyService
 	adminService  service.AdminService
 }
 
 // NewUsageHandler creates a new admin usage handler
 func NewUsageHandler(
 	usageService *service.UsageService,
-	apiKeyService *service.ApiKeyService,
+	apiKeyService *service.APIKeyService,
 	adminService service.AdminService,
 ) *UsageHandler {
 	return &UsageHandler{
@@ -125,7 +125,7 @@ func (h *UsageHandler) List(c *gin.Context) {
 	params := pagination.PaginationParams{Page: page, PageSize: pageSize}
 	filters := usagestats.UsageLogFilters{
 		UserID:      userID,
-		ApiKeyID:    apiKeyID,
+		APIKeyID:    apiKeyID,
 		AccountID:   accountID,
 		GroupID:     groupID,
 		Model:       model,
@@ -207,7 +207,7 @@ func (h *UsageHandler) Stats(c *gin.Context) {
 	}
 
 	if apiKeyID > 0 {
-		stats, err := h.usageService.GetStatsByApiKey(c.Request.Context(), apiKeyID, startTime, endTime)
+		stats, err := h.usageService.GetStatsByAPIKey(c.Request.Context(), apiKeyID, startTime, endTime)
 		if err != nil {
 			response.ErrorFrom(c, err)
 			return
@@ -269,9 +269,9 @@ func (h *UsageHandler) SearchUsers(c *gin.Context) {
 	response.Success(c, result)
 }
 
-// SearchApiKeys handles searching API keys by user
+// SearchAPIKeys handles searching API keys by user
 // GET /api/v1/admin/usage/search-api-keys
-func (h *UsageHandler) SearchApiKeys(c *gin.Context) {
+func (h *UsageHandler) SearchAPIKeys(c *gin.Context) {
 	userIDStr := c.Query("user_id")
 	keyword := c.Query("q")
 
@@ -285,22 +285,22 @@ func (h *UsageHandler) SearchApiKeys(c *gin.Context) {
 		userID = id
 	}
 
-	keys, err := h.apiKeyService.SearchApiKeys(c.Request.Context(), userID, keyword, 30)
+	keys, err := h.apiKeyService.SearchAPIKeys(c.Request.Context(), userID, keyword, 30)
 	if err != nil {
 		response.ErrorFrom(c, err)
 		return
 	}
 
 	// Return simplified API key list (only id and name)
-	type SimpleApiKey struct {
+	type SimpleAPIKey struct {
 		ID     int64  `json:"id"`
 		Name   string `json:"name"`
 		UserID int64  `json:"user_id"`
 	}
 
-	result := make([]SimpleApiKey, len(keys))
+	result := make([]SimpleAPIKey, len(keys))
 	for i, k := range keys {
-		result[i] = SimpleApiKey{
+		result[i] = SimpleAPIKey{
 			ID:     k.ID,
 			Name:   k.Name,
 			UserID: k.UserID,

backend/internal/handler/admin/user_handler.go

@@ -243,9 +243,9 @@ func (h *UserHandler) GetUserAPIKeys(c *gin.Context) {
 		return
 	}
 
-	out := make([]dto.ApiKey, 0, len(keys))
+	out := make([]dto.APIKey, 0, len(keys))
 	for i := range keys {
-		out = append(out, *dto.ApiKeyFromService(&keys[i]))
+		out = append(out, *dto.APIKeyFromService(&keys[i]))
 	}
 	response.Paginated(c, out, total, page, pageSize)
 }