feat(audit): F1+F2 告警静默规则标记完成 + 审计日志CSV导出实现

F1 告警静默规则 [done]:
- 后端 alert_silence.go: CRUD + Toggle (onetime/daily/weekly 三模式)
- 告警引擎 isSilenced 集成 (alert_engine.go)
- 前端 SilenceRuleTab + SilenceDialog
- 路由 /alerts/silences 已注册

F2 审计日志导出 [done]:
- 重写 ExportAuditLogs: 真正的 CSV 导出 (encoding/csv + UTF-8 BOM)
- 支持 module/action/username/startTime/endTime 筛选
- 导出限制 10000 条防溢出，自动记录审计日志
- JSON 格式向后兼容 (format=json)
- 前端 exportLogs 传递查询参数

同时包含累积的前期工作:
- 目录重构 internal/ -> controller/model/router (v0.55-v0.57)
- 后端分层架构 dto/repository/service/utils
- 审计模块全功能 (终端审计/操作审计/登录日志)
- asciicast v2 录制格式
- SFTP 文件浏览器
- StatStrip 紧凑统计条
- 在线会话自动刷新
- LiveMonitor WebSocket 诊断修复

验证: go build ✅ | npm run build ✅ | Docker 部署 ✅ | 10 回归端点 ✅ | CSV 导出 ✅ | 静默 CRUD ✅

backend/controller/automation.go

@@ -0,0 +1,76 @@
+package controller
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"os/exec"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+// randomCode returns a short unique code for records that require a unique
+// string identifier (e.g. playbooks). It combines a unix timestamp with 4
+// random hex bytes to guarantee uniqueness even under rapid sequential inserts.
+func randomCode(prefix string) string {
+	b := make([]byte, 4)
+	_, _ = rand.Read(b)
+	return fmt.Sprintf("%s-%d-%s", prefix, time.Now().Unix(), hex.EncodeToString(b))
+}
+
+// runLocal executes a script or shell command locally on the AIOps host and
+// returns the combined stdout+stderr output, the process exit code (0 = success)
+// and the wall-clock duration in milliseconds. A timeout prevents runaway jobs.
+func runLocal(scriptType, content string, timeoutSec int) (output string, exitCode int, durationMs int) {
+	start := time.Now()
+	timeout := time.Duration(timeoutSec) * time.Second
+	if timeout <= 0 {
+		timeout = 300 * time.Second
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	var cmd *exec.Cmd
+	switch scriptType {
+	case "python":
+		cmd = exec.CommandContext(ctx, "python3", "-c", content)
+	default: // shell / command / "" → run via bash
+		cmd = exec.CommandContext(ctx, "bash", "-c", content)
+	}
+
+	var out bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = &out
+
+	err := cmd.Run()
+	durationMs = int(time.Since(start).Milliseconds())
+	output = out.String()
+
+	if ctx.Err() == context.DeadlineExceeded {
+		output += fmt.Sprintf("\n[超时] 执行超过 %d 秒被终止", timeoutSec)
+		return output, -1, durationMs
+	}
+	if err != nil {
+		if exitError, ok := err.(*exec.ExitError); ok {
+			exitCode = exitError.ExitCode()
+		} else {
+			exitCode = -1
+			output += "\n" + err.Error()
+		}
+		return output, exitCode, durationMs
+	}
+	return output, 0, durationMs
+}
+
+// AutomationHandler 自动化运维处理器
+type AutomationHandler struct {
+	db *gorm.DB
+}
+
+// NewAutomationHandler 创建自动化运维处理器
+func NewAutomationHandler(db *gorm.DB) *AutomationHandler {
+	return &AutomationHandler{db: db}
+}