feat: 配置 golangci-lint 静态分析并修复存量违规

- 新增 backend/.golangci.yml 配置 12 个 linter（forbidigo、errorlint、errcheck、staticcheck、revive、gocritic、gosec、bodyclose、noctx、nilerr、goimports、gocyclo）
- 新增 lefthook.yml 配置 pre-commit hook 自动运行 lint
- 修复存量代码违规：errors.Is/As 替换、zap.Error 替换、import 排序、errcheck 修复
- 更新 README 补充编码规范说明
- 归档 backend-code-lint 变更

backend/cmd/desktop/dialog_darwin.go

@@ -6,19 +6,25 @@ import (
 	"fmt"
 	"os/exec"
 	"strings"
+
+	"go.uber.org/zap"
 )
 
 func showError(title, message string) {
 	script := fmt.Sprintf(`display dialog "%s" buttons {"OK"} default button "OK" with title "%s"`,
 		escapeAppleScript(message), escapeAppleScript(title))
-	exec.Command("osascript", "-e", script).Run()
+	if err := exec.Command("osascript", "-e", script).Run(); err != nil {
+		dialogLogger().Warn("显示错误对话框失败", zap.Error(err))
+	}
 }
 
 func showAbout() {
 	message := "Nex Gateway\n\nAI Gateway - 统一的大模型 API 网关\n\nhttps://github.com/nex/gateway"
 	script := fmt.Sprintf(`display dialog "%s" buttons {"OK"} default button "OK" with title "关于 Nex Gateway"`,
 		escapeAppleScript(message))
-	exec.Command("osascript", "-e", script).Run()
+	if err := exec.Command("osascript", "-e", script).Run(); err != nil {
+		dialogLogger().Warn("显示关于对话框失败", zap.Error(err))
+	}
 }
 
 func escapeAppleScript(s string) string {