fix: golangci-lint 零告警通过 (57→0) + gofumpt/goimports 全量格式化

## CI 修复 (P0/P1)

P0 — 编译阻塞:
  - interfaces.go: postUseCase ISP 接口移除不用的 Create/Update/Delete

P1 — 必须修复:
  - ST1000: 为 13 个包添加包注释 (common/config/model/service/...)
  - ST1005: redis_store.go 全部错误消息改为小写开头
  - errcheck (19处): defer Close()→闭包忽略, notifier.Create→_=, r.Run→检查error
  - errorlint (9处): switch-on-error→errors.Is 链, ==→errors.Is
  - ST1020/ST1022: 导出符号注释以符号名开头

P2 — 安全评审:
  - gosec (12处): G203/G301/G304/G306 添加 nolint 注释并附理由

P3 — 清理:
  - unused: 移除 hasUnicode/energyStore/current/energyAdminUseCase
  - gofumpt + goimports 全量格式化 (35+ 文件)

internal/controller/settings_api_profile.go

@@ -1,6 +1,7 @@
 package controller
 
 import (
+	"errors"
 	"net/http"
 	"strconv"
 
@@ -49,10 +50,9 @@ func (sc *SettingsController) UpdateProfile(c *gin.Context) {
 			hasCompleted, _ := sc.levelSvc.HasCompletedTask(userID, "username")
 			if hasCompleted {
 				if err := sc.energySvc.DeductOnRename(userID); err != nil {
-					switch err {
-					case common.ErrInsufficientEnergy:
+					if errors.Is(err, common.ErrInsufficientEnergy) {
 						common.Error(c, http.StatusBadRequest, "域能不足，无法改名。可通过每日签到或创作被赋能获取")
-					default:
+					} else {
 						common.Error(c, http.StatusInternalServerError, "操作失败")
 					}
 					return
@@ -81,10 +81,9 @@ func (sc *SettingsController) UpdateProfile(c *gin.Context) {
 		hasCompleted, _ := sc.levelSvc.HasCompletedTask(userID, "username")
 		if hasCompleted {
 			if err := sc.energySvc.DeductOnRename(userID); err != nil {
-				switch err {
-				case common.ErrInsufficientEnergy:
+				if errors.Is(err, common.ErrInsufficientEnergy) {
 					common.Error(c, http.StatusBadRequest, "域能不足，无法改名。可通过每日签到或创作被赋能获取")
-				default:
+				} else {
 					common.Error(c, http.StatusInternalServerError, "操作失败")
 				}
 				return
@@ -122,7 +121,7 @@ func (sc *SettingsController) UploadAvatar(c *gin.Context) {
 		common.Error(c, http.StatusBadRequest, "请选择文件")
 		return
 	}
-	defer file.Close()
+	defer func() { _ = file.Close() }()
 
 	// 裁切参数（可选，来自前端裁切弹窗）
 	cropX, _ := strconv.Atoi(c.PostForm("crop_x"))