docs: add Swagger annotations to 13 API handlers

Added @Summary, @Description, @Tags, @Param, @Success, @Failure,
@Router annotations to all major handler endpoints for OpenAPI/Swagger
auto-generation. Covers 86 annotations across:

- auth_handler.go (25): all auth endpoints
- user_handler.go (14): CRUD + roles + admin management
- device_handler.go (13): device CRUD + trust management
- role_handler.go (8): role CRUD + permissions
- custom_field_handler.go (7): field CRUD + user values
- permission_handler.go (7): permission CRUD + tree
- log_handler.go (3): login/operation logs
- captcha_handler.go (3): generate/verify
- stats_handler.go (2): dashboard + user stats
- avatar_handler.go (1): upload avatar
- totp_handler.go (1): totp status
- password_reset_handler.go (1): forgot password

Partially addresses P2: missing Swagger annotations
(PRODUCTION_GAP_ANALYSIS_2026-04-08)

internal/api/handler/totp_handler.go

@@ -22,6 +22,15 @@ func NewTOTPHandler(authService *service.AuthService, totpService *service.TOTPS
 	}
 }
 
+// GetTOTPStatus 获取TOTP状态
+// @Summary 获取TOTP状态
+// @Description 获取当前用户的TOTP两步验证状态
+// @Tags 两步验证
+// @Produce json
+// @Security BearerAuth
+// @Success 200 {object} Response{data=TOTPStatusResponse} "TOTP状态"
+// @Failure 401 {object} Response "未认证"
+// @Router /api/v1/auth/totp/status [get]
 func (h *TOTPHandler) GetTOTPStatus(c *gin.Context) {
 	userID, ok := getUserIDFromContext(c)
 	if !ok {