chore(psr4): phase 3 — namespace Public controllers (final layer)

Namespace all 174 Public controllers into XcVm\Public\Controllers\<Admin|Api|
Player|Reseller>, completing the per-file namespace migration. View templates and
entry points (index.php, admin/*.php, stream/*.php, progress/, routes/*.php,
Views/*) stay procedural/global and only gain use imports.

- Split the 3 multi-class Api files per PSR-4: AdminApiController→+AdminAPIWrapper,
  Enigma2ApiController→+SimpleXMLExtended (extends \SimpleXMLElement),
  ResellerRestApiController→+ResellerAPIWrapper (use-block copied to each new file).
- Add use to referrers — the procedural route files (routes/admin|player|reseller.php)
  and index.php now import each routed controller; sibling controllers extend their
  base class in the same namespace.
- Qualify built-ins/ioncube/global in the namespaced controllers (\Exception,
  \DateTime, \PDO, \SimpleXMLElement, \ZipArchive, \ReflectionClass,
  \XC_Bootstrap, \XC_VM, ...). Verified zero unresolved classes by temporarily
  analysing src/Public/Controllers under PHPStan, then reverting to scanDirectories
  (the ~346 pre-existing legacy findings there are out of scope for this migration).

Verified: php -l clean; PHPStan no errors; PHPUnit 295/295; no global controller
class-files remain; leading-backslash re-sweep clean.

src/Public/Controllers/Admin/QueueController.php

@@ -1,5 +1,7 @@
 <?php
 
+namespace XcVm\Public\Controllers\Admin;
+
 /**
  * QueueController — Encoding Queue.
  *
@@ -8,7 +10,7 @@
  * @package XC_VM_Public_Controllers_Admin
  * @author  Divarion_D <https://github.com/Divarion-D>
  * @copyright 2025-2026 Vateron Media
- * @link    https://github.com/Vateron-Media/XC_VM
+ * @link    https://github.com/Vateron-Media/\XC_VM
  * @license AGPL-3.0 https://www.gnu.org/licenses/agpl-3.0.html
  */