docs: 电脑操作模式进度存档（暂停待续）+ 调试脚本

- docs/computer-use-PROGRESS.md: 已完成/已知问题/关键机制踩坑记录
- tools/test-enum.ps1: EnumWindows 基准脚本（本机验证可用）
- PLAN.md 更新：阶段3进行中，因余额暂停

tools/test-enum.ps1

@@ -0,0 +1,28 @@
+Add-Type -TypeDefinition @'
+using System;using System.Runtime.InteropServices;using System.Text;
+public class W {
+ [DllImport("user32.dll")] public static extern bool EnumWindows(EnumProc cb, IntPtr l);
+ [DllImport("user32.dll")] public static extern int GetWindowText(IntPtr h, StringBuilder s, int n);
+ [DllImport("user32.dll")] public static extern int GetWindowTextLength(IntPtr h);
+ [DllImport("user32.dll")] public static extern bool IsWindowVisible(IntPtr h);
+ [DllImport("user32.dll")] public static extern bool GetWindowRect(IntPtr h, out RECT r);
+ public delegate bool EnumProc(IntPtr h, IntPtr l);
+ [StructLayout(LayoutKind.Sequential)] public struct RECT { public int Left,Top,Right,Bottom; }
+}
+'@
+$list = New-Object System.Collections.ArrayList
+$cb = [W+EnumProc]{ param($h,$l)
+  if ([W]::IsWindowVisible($h)) {
+    $len = [W]::GetWindowTextLength($h)
+    if ($len -gt 0) {
+      $sb = New-Object System.Text.StringBuilder($len + 1)
+      [W]::GetWindowText($h,$sb,$sb.Capacity) | Out-Null
+      $r = New-Object W+RECT
+      [W]::GetWindowRect($h,[ref]$r) | Out-Null
+      [void]$list.Add(("{0}|{1}|{2},{3},{4},{5}" -f $h,$sb.ToString(),$r.Left,$r.Top,$r.Right,$r.Bottom))
+    }
+  }
+  return $true
+}
+[W]::EnumWindows($cb,[IntPtr]::Zero) | Out-Null
+$list | ForEach-Object { Write-Output $_ }