[BUGFIX] Fix corrupted JavaScript assets loaded by website users

Website users loaded corrupted JavaScript assets for files generated by
EXT:vhs when EXT:vhs was in the middle of re-writing the contents of the
requested asset file. This happens because EXT:core
`GeneralUtility::writeFile()` isn't implemented in an atomic style
causing observers (such as visiting website users) to read incomplete
asset file contents. Incomplete JavaScript files likely cause syntax
errors when interpreted by the user's user-agent rendering front end
sites unable to reach JavaScript-based interactivity.

Fix the issue by (non-atomically) writing into a temporary file and
replacing the destination asset file with a single atomic `rename()`
operation instead. This ensures that observers of the destination asset
file either see the complete old contents or the complete new contents
but never any intermediate state of the asset content.

See: https://man7.org/linux/man-pages/man2/rename.2.html
See: https://github.com/TYPO3/typo3/blob/v10.4.37/typo3/sysext/core/Classes/Utility/GeneralUtility.php#L1835-L1861

Author: adamkoppede

Classes/Service/AssetService.php

@@ -712,7 +712,24 @@ protected function writeFile(string $file, string $contents): void
         $signalSlotDispatcher->dispatch(__CLASS__, static::ASSET_SIGNAL, [&$file, &$contents]);
         */
 
-        GeneralUtility::writeFile($file, $contents, true);
+        $tmpFile = @tempnam(dirname($file), basename($file));
+        if ($tmpFile === false) {
+            $error = error_get_last();
+            $details = $error !== null ? ": {$error['message']}" : ".";
+            throw new \RuntimeException(
+                "Failed to create temporary file for writing asset {$file}{$details}",
+                1733258066
+            );
+        }
+        GeneralUtility::writeFile($tmpFile, $contents, true);
+        if (@rename($tmpFile, $file) === false) {
+            $error = error_get_last();
+            $details = $error !== null ? ": {$error['message']}" : ".";
+            throw new \RuntimeException(
+                "Failed to move asset-backing file {$file} into final destination{$details}",
+                1733258156
+            );
+        }
     }
 
     protected function mergeArrays(array $array1, array $array2): array