fix(windows): address native CI review findings

packages/util/paths/src/index.ts

@@ -4,7 +4,7 @@
  * @module @deepseek-ai/dsh-paths
  */
 
-import { realpath } from 'node:fs/promises'
+import { opendir, realpath } from 'node:fs/promises'
 import { homedir } from 'node:os'
 import { basename, dirname, join, resolve } from 'node:path'
 
@@ -20,19 +20,29 @@ export const DSH_HOME_ENV = 'DSH_HOME'
 /**
  * Give a native filesystem watcher one canonical spelling of a path, even
  * when its final components do not exist yet. The deepest existing ancestor
- * is resolved through {@link realpath}; the missing suffix is then restored.
- * This prevents Windows short-name aliases from being mixed with long paths
- * emitted by the native watcher backend.
+ * is resolved through {@link realpath}; when a suffix is missing, that
+ * ancestor is also proved to be an enumerable directory before the suffix is
+ * restored. This prevents Windows from treating a regular-file ancestor as
+ * ordinary absence, and prevents short-name aliases from being mixed with
+ * long paths emitted by the native watcher backend.
  * @param path - Watch target or root, resolved against the current directory.
  * @returns the target with its existing ancestor canonicalized.
- * @throws when ancestor traversal encounters an error other than absence.
+ * @throws when ancestor traversal encounters an error other than absence, or
+ * the existing ancestor of a missing suffix is not an enumerable directory.
  */
 export async function canonicalizeWatchPath(path: string): Promise<string> {
   let current = resolve(path)
   const missing: string[] = []
   while (true) {
     try {
-      return join(await realpath(current), ...missing.reverse())
+      const canonical = await realpath(current)
+      if (missing.length > 0) {
+        // A Windows file-as-parent probe reports ENOENT. Opening the resolved
+        // ancestor preserves the cross-platform directory requirement.
+        const directory = await opendir(canonical)
+        await directory.close()
+      }
+      return join(canonical, ...missing.reverse())
     } catch (error) {
       if ((error as NodeJS.ErrnoException).code !== 'ENOENT') throw error
       const parent = dirname(current)