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/service/audit_service.go

@@ -56,14 +56,14 @@ type avatarFileCleaner interface {
 
 // AuditService 审核业务逻辑
 type AuditService struct {
-	auditRepo        auditRepo
-	userRepo         userProfileStore
-	settings         siteSettingsChecker
-	defaultCfg       config.AuditConfig
-	notifier         auditNotifier
-	levelSvc         auditTaskCompleter
-	energyRefundSvc  energyRenameRefunder
-	avatarCleaner    avatarFileCleaner
+	auditRepo       auditRepo
+	userRepo        userProfileStore
+	settings        siteSettingsChecker
+	defaultCfg      config.AuditConfig
+	notifier        auditNotifier
+	levelSvc        auditTaskCompleter
+	energyRefundSvc energyRenameRefunder
+	avatarCleaner   avatarFileCleaner
 }
 
 // NewAuditService 构造函数