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/router/middlewares.go

@@ -63,7 +63,7 @@ func loggerMiddleware() gin.HandlerFunc {
 
 func logRequest(ctx context.Context, c *gin.Context, path string, start, end time.Time, latency time.Duration) {
 	format := "[LoggerMiddleware] %s %s\nStartTime: %s\nEndTime: %s\nLatency: %d\nClientIP: %s\nResponse: %d %d"
-	args := []interface{}{
+	args := []any{
 		c.Request.Method,
 		path,
 		start.Format(time.RFC3339),
@@ -89,8 +89,8 @@ func isOriginAllowed(ctx context.Context, origin string) bool {
 	if err != nil || sc.Value == "" {
 		return false
 	}
-	allowedOrigins := strings.Split(sc.Value, ",")
-	for _, allowed := range allowedOrigins {
+	allowedOrigins := strings.SplitSeq(sc.Value, ",")
+	for allowed := range allowedOrigins {
 		allowed = strings.TrimRight(strings.TrimSpace(allowed), "/")
 		if allowed != "" && strings.EqualFold(allowed, origin) {
 			return true
@@ -109,7 +109,7 @@ func corsMiddleware() gin.HandlerFunc {
 			c.Writer.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS, GET, PUT, DELETE, PATCH")
 		}
 
-		if c.Request.Method == "OPTIONS" {
+		if c.Request.Method == http.MethodOptions {
 			c.AbortWithStatus(http.StatusNoContent)
 			return
 		}