fix(picker): correct crash-isolation and DPI claims, wire the built-worker guard, and tidy round-four nits

The round-four review's v6 pass found three factual gaps and the v5 pass two
nits. Correct them before merge:

- The in-process note claimed a koffi signature mistake is 'contained to
  the worker thread' — worker_threads share the process, so a native access
  violation takes down the whole Node process with no PowerShell fallback.
  State the real blast radius and record the deferred pkg-VFS worker-spawn
  arm in Consequences (both languages, pairing re-recorded).
- The 2026-07-27 picker note claimed unconditional 'per-monitor-v2 DPI';
  PMv2-less hosts (Server 2016 / Win10 1607) cascade to per-monitor or
  system-aware. Say 'the best thread DPI awareness the host accepts'
  (both languages, pairing re-recorded).
- built-worker.e2e.ts was not in any keyless gate (vitest.e2e config is
  not part of the default unit run and builtBinSmokeGate's explicit list
  missed it), so lib/worker.cjs load regressions passed keyless CI. Add it
  to builtBinSmokeGate alongside the workflow-workerthread sibling.
- Remove the dead trailing 'void bindings' in win32-dialog-logic.spec.ts
  and give native-picker.spec.ts the sibling module header it lacked.

.agents/notes/implemented/feature/2026-08-02-win32-in-process-folder-dialog.zh.md

@@ -23,4 +23,5 @@ Windows 目录选择器的主层此前是围绕 WinForms `FolderBrowserDialog`
 
 - 每台 Windows 机器都得到带其所支持的最佳 DPI 感知（1703+ 为 per-monitor-v2）的现代对话框，无论是否安装 PowerShell；PowerShell 层只服务 koffi 无法驱动 COM 的主机。
 - 真实对话框渲染与选中路径仍是手动 Windows 检查（自动关闭冒烟证明打开／中止／收尾）；卡死的中止可能泄漏一个对话框线程直到进程退出，已记录于包 README。
-- 所用 COM vtable 槽位与 GUID 是冻结的 Windows ABI（Vista 起）；koffi 签名错误是被限制在 worker 线程内的进程内崩溃风险，并在交付前被 win32 冒烟捕获。
+- 所用 COM vtable 槽位与 GUID 是冻结的 Windows ABI（Vista 起）；koffi 签名错误是可能拖垮整个 Node 进程的原生崩溃风险——`worker_threads` 与主线程共享进程，访问冲突不会只局限在 worker 内，也不会进入 PowerShell 回退。mocked-koffi 的 ABI 钉与真实 win32 冒烟正是为了在交付前捕获这类错误。
+- 打包二进制的 VFS 臂——在 pkg 快照内解析 `./worker.cjs`——不受任何自动化测试覆盖：源码 worker 与普通 Node 下构建出的 `lib/worker.cjs` 已被覆盖，VFS 专属的 spawn 推迟到 Windows CI 路线图。