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/edge/updater/restart_unix.go

@@ -1,9 +1,13 @@
 //go:build !windows
 
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
 // Package updater provides capabilities to check for, download, and apply updates.
 package updater
 
 import (
+	"errors"
 	"fmt"
 	"log/slog"
 	"os"
@@ -19,7 +23,7 @@ func replaceAndRestart(execPath string, tmpPath string) error {
 		renameErr := err
 		if err := os.Remove(tmpPath); err != nil && !os.IsNotExist(err) {
 			slog.Error("remove tmp binary failed", "path", tmpPath, "error", err)
-			return fmt.Errorf("backup current binary: %w; remove tmp binary: %v", renameErr, err)
+			return fmt.Errorf("backup current binary: %w; remove tmp binary: %w", renameErr, err)
 		}
 		return fmt.Errorf("backup current binary: %w", renameErr)
 	}
@@ -27,7 +31,7 @@ func replaceAndRestart(execPath string, tmpPath string) error {
 		replaceErr := err
 		if err := os.Rename(backupPath, execPath); err != nil {
 			slog.Error("restore backup binary failed", "path", backupPath, "error", err)
-			return fmt.Errorf("replace binary: %w; restore backup binary: %v", replaceErr, err)
+			return fmt.Errorf("replace binary: %w; restore backup binary: %w", replaceErr, err)
 		}
 		return fmt.Errorf("replace binary: %w", replaceErr)
 	}
@@ -37,7 +41,7 @@ func replaceAndRestart(execPath string, tmpPath string) error {
 	if err := syscall.Exec(execPath, os.Args, os.Environ()); err != nil { //nolint:gosec // execPath is the validated edge updater binary path
 		return fmt.Errorf("exec restart: %w", err)
 	}
-	return fmt.Errorf("unreachable after exec")
+	return errors.New("unreachable after exec")
 }
 
 func removeBackupBinary(path string) error {