refactor(lock): use JSON for file lock metadata

- Replace file lock serialize/unserialize metadata handling with JSON
- Keep explicit owner and expiry validation after decoding
- Use JSON_THROW_ON_ERROR for encode and decode failures"

Signed-off-by: memleakd <121398829+memleakd@users.noreply.github.com>

Author: memleakd

system/Cache/LockStores/FileLockStore.php

@@ -146,7 +146,7 @@ private static function readLockData($handle): ?array
         }
 
         try {
-            $data = unserialize($content);
+            $data = json_decode($content, true, flags: JSON_THROW_ON_ERROR);
         } catch (Throwable) {
             return null;
         }
@@ -169,7 +169,13 @@ private static function writeLockData($handle, string $owner, int $expires): boo
             return false;
         }
 
-        if (fwrite($handle, serialize(['owner' => $owner, 'expires' => $expires])) === false) {
+        try {
+            $content = json_encode(['owner' => $owner, 'expires' => $expires], JSON_THROW_ON_ERROR);
+        } catch (Throwable) {
+            return false;
+        }
+
+        if (fwrite($handle, $content) === false) {
             return false;
         }