feat(picker): open the Win32 folder dialog in-process over koffi

The modern IFileOpenDialog becomes the primary win32 tier: a koffi-driven
COM conversation on a worker_threads worker (the modal Show never blocks
the host event loop), per-monitor-v2 DPI via SetThreadDpiAwarenessContext,
and abort service by re-posting WM_CLOSE to the dialog thread's windows,
with terminate+unref as the last resort (Node cannot interrupt a thread
blocked in native code, and such a worker must never hold the process open).

The PowerShell chain stays as the fallback tier with its trigger widened
from ENOENT to any pwsh failure, closing the review-flagged PowerShell 6
regression (no WinForms: exit 1, not ENOENT, so 5.1 never ran).

Layering keeps per-file coverage honest on every host: pure sequencing and
the driver test against fakes anywhere; the bindings run against a mocked
koffi COM world (the session-persistence-jsonl technique); POSIX hosts
drive the real spawn plumbing to its koffi-load rejection; win32 hosts run
a real open-and-abort-close smoke. The smoke joins processBoundTests: a
worker blocked in a native modal wedges the threads pool's teardown, while
a fork contains it. The worker bundles as its own CJS tsdown entry
(workflow-workerthread's pattern; no TLA), and the host module is imported
statically so the node-half bundle stays chunk-free.

Built-plane and real-COM behavior verified on native Windows: standalone
probes for the source worker, the built CJS worker, and the driver's abort
path all open and close the real dialog.

Agent Notes: new implemented/feature/2026-08-02-win32-in-process-folder-dialog
(bilingual) owns the decision; the DPI note is re-scoped to the fallback tier
it now describes and its AutoUpgradeEnabled attribution corrected (.NET Core
3.0 rewrote FolderBrowserDialog; the opt-out arrived in .NET 6).

packages/host/directory-picker-native/tsdown.config.ts

@@ -1,3 +1,18 @@
 import { clientBundle } from '../../client/tsdown.client.ts'
 
-export default clientBundle('@deepseek-ai/dsh-host-directory-picker-native', ['lib/types/index.js', 'lib/types/invariant.js'])
+// The Win32 dialog worker builds as its own CJS entry (mirroring
+// dsh-workflow-workerthread's worker): path-loaded by the driver, inlining
+// the dialog logic while koffi stays an external native require.
+export default [
+  ...clientBundle('@deepseek-ai/dsh-host-directory-picker-native', ['lib/types/index.js', 'lib/types/invariant.js']),
+  {
+    entry: ['lib/types/win32-dialog-worker.js'],
+    outDir: 'lib',
+    format: ['cjs'] as ['cjs'],
+    platform: 'node' as const,
+    target: 'es2024',
+    fixedExtension: false,
+    dts: false,
+    clean: false,
+  },
+]