refactor: extract buildSearchConditions, add getThesesList, remove dead code, fix SearchTest

- Database: extract private buildSearchConditions(array $params): array shared by
  searchTheses() and countSearchResults(), eliminating ~80 lines of duplication;
  add array type hints to both public methods
- Database: add getThesesList(array $filters) and getAllYears() so admin/index.php
  no longer builds raw SQL inline
- admin/index.php: replace inline PDO query block with $db->getThesesList() /
  $db->getAllYears(); drop the now-unused $pdo local
- config/bootstrap.php: remove dead include_template() helper and the
  vendor/autoload.php Composer stub (no vendor/ directory exists)
- apps/: delete entire directory (leftover artefact, no code references it)
- tests/Integration/SearchTest.php: fix three searchTheses() calls from bare
  strings to proper array params to match the method signature (prevented TypeError)

config/bootstrap.php

@@ -24,21 +24,7 @@ if (php_sapi_name() === 'cli-server') {
     ini_set('log_errors', '1');
 }
 
-// Simple helper function for including templates
-function include_template($name)
-{
-    $path = APP_ROOT . '/templates/' . $name;
-    if (file_exists($path)) {
-        include $path;
-    }
-}
-
 // Load admin credentials if available (defines ADMIN_PASSWORD_HASH for AdminAuth)
 if (file_exists(APP_ROOT . '/config/admin_credentials.php')) {
     require_once APP_ROOT . '/config/admin_credentials.php';
 }
-
-// Autoload Composer dependencies if available
-if (file_exists(APP_ROOT . '/vendor/autoload.php')) {
-    require_once APP_ROOT . '/vendor/autoload.php';
-}