docs(php): add standardized file headers across codebase

- Add @author, @copyright, @link, @version, @license to 399 PHP files
- MERGE mode: inject metadata into 243 existing docblocks (preserving docs)
- INSERT mode: create new docblocks for 156 files without headers
- Skip 3 files that already had correct headers
- Exclude third-party libs (TMDb, mobiledetect, Dropbox, etc.)
- Exclude bin/, ministra/, content/, tmp/, resources/, module views
- Update tools/add_headers.php to v2 with MERGE strategy

src/core/Process/ProcessManager.php

@@ -26,6 +26,12 @@
  *   ProcessManager::acquireCronLock('/tmp/cron_streams.pid', 1800);
  *   // ... do work ...
  *   // Lock file cleaned up automatically on exit
+ *
+ * @package XC_VM_Core_Process
+ * @author  Divarion_D <https://github.com/Divarion-D>
+ * @copyright 2025-2026 Vateron Media
+ * @link    https://github.com/Vateron-Media/XC_VM
+ * @license AGPL-3.0 https://www.gnu.org/licenses/agpl-3.0.html
  */
 
 class ProcessManager {