Harden web root, secrets and realtime auth

- .htaccess: refuse .git, .env, docker, nodejs, sdlc*, scripts, archives and
  app internals; security headers, HSTS over TLS, optional HTTPS redirect
- uploads served through app/file.php to signed-in users only
- Apache/PHP hardening config for the container (ServerTokens, expose_php)
- least-privilege DB account and APP_SECRET_KEY via docker/php/provision.php;
  SMTP passwords re-encrypted with a random IV (secret_box.php)
- Socket.IO rooms from a PHP-signed token; /emit and cron refuse empty secrets
- escape notification text; CLI guards on build scripts; no fixed demo password

scripts/format_progress_status_html.php

@@ -1,6 +1,12 @@
 <?php
 declare(strict_types=1);
 
+// Build script, CLI only — the repository sits under the web root.
+if (PHP_SAPI !== 'cli') {
+    http_response_code(404);
+    exit;
+}
+
 /*
  * Applies the approved print layout from the first formatted Progress Status
  * Record to every generated Progress Status Record HTML file. Markdown source