后端与全仓代码质量清理（golangci 扩展集 · 测试质量 · 并发安全 · 文档同步）

代码质量全量清理，零行为变化：golangci 扩展集 13 类 linter（gosec/modernize/perfsprint/canonicalheader/usestdlibvars/wastedassign/intrange/errorlint/forcetypeassert/recvcheck/exhaustive/unparam）全量修复，测试代码质量（testifylint/thelper/usetesting）25→0，frpc 进程生命周期真 bug（进程组击杀）、全仓 go test -race 6 类数据竞争（含 1 个生产竞争）、SPDX license 头补齐 131 文件、前端测试套件 next-intl 迁移后 44 失败→全绿、过期 swagger 文档重新生成、pnpm-workspace 构建审批。

Experiments: #2-#17, #18, #20, #21, #23
Metric: total_issues 108 → 8 (-92.6%)

internal/apps/upload/ingest/helpers.go

@@ -59,8 +59,8 @@ func validateAllowedExtension(ctx context.Context, ext string) error {
 		return nil
 	}
 
-	allowedExts := strings.Split(strings.ToLower(sc.Value), ",")
-	for _, allowedExt := range allowedExts {
+	allowedExts := strings.SplitSeq(strings.ToLower(sc.Value), ",")
+	for allowedExt := range allowedExts {
 		if strings.TrimSpace(allowedExt) == ext {
 			return nil
 		}

internal/apps/upload/ingest/ingest.go

@@ -54,6 +54,8 @@ func ingestWithHashPolicy(ctx context.Context, req Request) (Result, error) {
 				return Result{}, ErrStorageReadOnly
 			}
 			return createDedupRecord(ctx, existing, req)
+		case PolicyCreate:
+			// 忽略已存在记录，走下方的新建流程。
 		}
 	}
 	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {

internal/apps/upload/ingest/ingest_test.go

@@ -513,6 +513,7 @@ func loadTotalStats(ctx context.Context) (totalStatsSnapshot, error) {
 }
 
 func setupMockStorage(t *testing.T, putCount *int) (restore func(), disable func()) {
+	t.Helper()
 	return setupMockStorageWithDeleteCount(t, putCount, nil)
 }