fix(process): kill 兜底弃 taskkill 命令行, 改 Windows API 进程树强杀

- Toolhelp32 快照枚举父子关系→收集后代(防环)→OpenProcess+TerminateProcess 按 PID 定向结束
- 产品红线: 系统操作禁拼 cmd 命令字符串(2026-10-09 用户令, 与 zomaintain AGENTS §一同源)
- wire 不变: 仅错误文案 taskkill 段改'进程树终止'

process/killtree_windows.go

@@ -0,0 +1,78 @@
+//go:build windows
+
+// 进程树强杀(编程方式, Windows API)——2026-10-09 起替代原 taskkill /F /T 命令行兜底
+// (产品红线: 系统操作禁拼 cmd 命令字符串)。
+package process
+
+import (
+	"fmt"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+// killProcessTree 按 PID 定向结束进程及其全部后代:
+// Toolhelp32 快照枚举全进程父子关系 → 收集后代(防父子环) → 逐个 OpenProcess+TerminateProcess。
+func killProcessTree(root uint32) error {
+	parentOf, err := snapshotParentMap()
+	if err != nil {
+		return err
+	}
+	var pids []uint32
+	visited := map[uint32]bool{}
+	var visit func(pid uint32)
+	visit = func(pid uint32) {
+		if visited[pid] {
+			return
+		}
+		visited[pid] = true
+		pids = append(pids, pid)
+		for child, parent := range parentOf {
+			if parent == pid {
+				visit(child)
+			}
+		}
+	}
+	visit(root)
+
+	var firstErr error
+	for _, pid := range pids {
+		h, err := windows.OpenProcess(windows.PROCESS_TERMINATE, false, pid)
+		if err != nil {
+			if firstErr == nil {
+				firstErr = fmt.Errorf("pid=%d OpenProcess: %w", pid, err)
+			}
+			continue
+		}
+		if err := windows.TerminateProcess(h, 1); err != nil {
+			if firstErr == nil {
+				firstErr = fmt.Errorf("pid=%d TerminateProcess: %w", pid, err)
+			}
+		}
+		_ = windows.CloseHandle(h)
+	}
+	return firstErr
+}
+
+// snapshotParentMap 全进程快照: pid → 父 pid。
+func snapshotParentMap() (map[uint32]uint32, error) {
+	snap, err := windows.CreateToolhelp32Snapshot(windows.TH32CS_SNAPPROCESS, 0)
+	if err != nil {
+		return nil, fmt.Errorf("CreateToolhelp32Snapshot: %w", err)
+	}
+	defer windows.CloseHandle(snap)
+
+	parentOf := map[uint32]uint32{}
+	var pe windows.ProcessEntry32
+	pe.Size = uint32(unsafe.Sizeof(pe))
+	if err := windows.Process32First(snap, &pe); err != nil {
+		return nil, fmt.Errorf("Process32First: %w", err)
+	}
+	for {
+		parentOf[pe.ProcessID] = pe.ParentProcessID
+		if err := windows.Process32Next(snap, &pe); err != nil {
+			break
+		}
+	}
+	return parentOf, nil
+}