Enhance security and input sanitization across multiple files

- Added a new tools.security.php file containing functions for sanitizing filenames, paths, and user inputs to prevent directory traversal and XSS attacks.
- Updated various files to utilize the new sanitization functions (Sf, Si) for user inputs and file operations, ensuring safer handling of data.
- Improved HTML output safety by applying htmlspecialchars to user-generated content in pre-body.php, cal.php, and other relevant files.
- Refactored user authentication and data retrieval processes in tools.auth.php and _login.php to enhance security and maintainability.
- Ensured consistent use of sanitization functions in API endpoints and admin functionalities to mitigate potential security vulnerabilities.

public_html/entreaulas/aulario.php

@@ -1,7 +1,9 @@
 <?php
 require_once "_incl/auth_redir.php";
 require_once "_incl/pre-body.php";
-$aulario_id = $_GET["id"];
+require_once "_incl/tools.security.php";
+
+$aulario_id = Sf($_GET["id"]);
 $centro_id = $_SESSION["auth_data"]["entreaulas"]["centro"];
 $aulario = json_decode(file_get_contents("/DATA/entreaulas/Centros/$centro_id/Aularios/$aulario_id.json"), true);
 ?>