fix(fs): replace execSync and fsync workarounds with atomic async FsHelpers operations to avoid XFS races and shell dependencies

ts/mod_unpack/classes.tsunpacker.ts

@@ -1,5 +1,4 @@
 import * as path from 'path';
-import { execSync } from 'child_process';
 import { TsPublishConfig } from '../mod_config/index.js';
 import { FsHelpers } from '../mod_fs/index.js';
 
@@ -83,10 +82,9 @@ export class TsUnpacker {
   /**
    * Perform the unpack operation - flatten nested output directories.
    *
-   * Uses shell commands (mv, rm) via execSync for reliability. Node.js async
-   * fs operations (rename, rm) can race on XFS filesystems where metadata
-   * commits are delayed, causing ENOENT or partial directory listings.
-   * Shell commands execute as direct syscalls without libuv's async layer.
+   * Renames the nested directory to a temp location, removes the dest dir,
+   * then renames the temp dir back as dest. Uses only rename operations
+   * which are atomic at the kernel level.
    *
    * Returns true if unpacking was performed, false if skipped.
    */
@@ -102,12 +100,17 @@ export class TsUnpacker {
     const nestedPath = this.getNestedPath();
     const tempPath = this.destDir + '.__unpack_temp__';
 
-    // Use shell commands for atomic, sequential filesystem operations.
-    // This avoids race conditions between Node.js async fs operations on XFS.
-    execSync(`rm -rf "${tempPath}"`, { stdio: 'ignore' });
-    execSync(`mv "${nestedPath}" "${tempPath}"`, { stdio: 'ignore' });
-    execSync(`rm -rf "${this.destDir}"`, { stdio: 'ignore' });
-    execSync(`mv "${tempPath}" "${this.destDir}"`, { stdio: 'ignore' });
+    // Step 1: Clean up any leftover temp dir from a previous failed run
+    await FsHelpers.removeDirectory(tempPath);
+
+    // Step 2: Rename nested → temp
+    await FsHelpers.move(nestedPath, tempPath);
+
+    // Step 3: Remove dest dir (now contains only sibling folders)
+    await FsHelpers.removeDirectory(this.destDir);
+
+    // Step 4: Rename temp → dest
+    await FsHelpers.move(tempPath, this.destDir);
 
     return true;
   }