feat: worker 日志 CSV 导出 + 集群日志导出菜单完善

- handleAuditWorkerLogsCsv: 全环 fan-out 收集每节点 frpc 日志,
  逐行展开为 CSV (node/worker_key/remote/worker_state/log_line),
  Excel 可直接过滤/pivot 审计
- gatherClusterWorkerLogs: 提取 JSON 与 CSV 共用的日志聚合逻辑
- 路由: GET /audit/worker-logs.csv (read 级)
- ClusterView: 导出 worker 日志改下拉菜单 (JSON/CSV 两格式)
- api.ts: downloadAuditCsv 支持 worker-logs 类型
- gofmt: handlers_audit.go 格式对齐

internal/httpapi/handlers_audit.go

@@ -172,6 +172,48 @@ func (h *Handler) handleAuditClusterLogCsv(w http.ResponseWriter, r *http.Reques
 		rows)
 }
 
+// handleAuditWorkerLogsCsv serves GET /audit/worker-logs.csv: every alive
+// node's frpc worker logs, fanned out over the ring and flattened to one row
+// per LOG LINE (node/worker/state columns repeated) so auditors can filter
+// and pivot in a spreadsheet. Unreachable nodes contribute an error row.
+func (h *Handler) handleAuditWorkerLogsCsv(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		methodNotAllowed(w)
+		return
+	}
+	if h.Ring == nil {
+		http.Error(w, "ring engine not enabled", http.StatusNotFound)
+		return
+	}
+	_, results := h.gatherClusterWorkerLogs(r)
+	rows := make([][]string, 0, 64)
+	for _, n := range results {
+		if !n.OK || n.Logs == nil {
+			rows = append(rows, []string{n.ID, "", "ERROR", n.Error, ""})
+			continue
+		}
+		for _, wk := range n.Logs.Workers {
+			// One row per line keeps the CSV rectangular; the tail's embedded
+			// newlines would otherwise need multi-line cells (RFC4180 allows
+			// them but Excel's filtering/pivot works better on flat rows).
+			for _, line := range strings.Split(strings.TrimRight(wk.Lines, "\n"), "\n") {
+				if ts, rest, found := strings.Cut(line, "."); found && len(ts) > 10 {
+					line = rest // strip the ANSI-prefixed timestamp prefix noise
+				}
+				line = strings.TrimSpace(line)
+				if line == "" {
+					continue
+				}
+				rows = append(rows, []string{n.ID, wk.Name, wk.Remote, wk.State, line})
+			}
+		}
+	}
+	writeCSV(w,
+		fmt.Sprintf("audit-worker-logs-%s.csv", time.Now().UTC().Format("20060102-150405")),
+		[]string{"node", "worker_key", "remote", "worker_state", "log_line"},
+		rows)
+}
+
 // rawJSON renders the log entry's payload as compact JSON (empty when absent)
 // for the lossless audit column.
 func rawJSON(data json.RawMessage) string {