Initial import of fitme3070.pt platform

Plain-PHP fleet platform with id.andmore.pt SSO. Wires shared/platform-tools
as a submodule (platform_update, backups, git/migration tools) like the other
platforms.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

site/_open.php

@@ -0,0 +1,19 @@
+<?php
+// Shared bootstrap + page-top chrome for the public site. Mirrors what the old
+// CI4 BaseController emitted before each Home action: seo + include (head/body)
+// + navbar + messenger chat. A page may set $current_uri_2 before including this.
+require_once __DIR__ . '/../config/db.php';
+require_once __DIR__ . '/../config/functions.php';
+
+if (empty($_SESSION['user_id']) && identity_is_federated()) {
+    sso_resolve_session($pdo);
+}
+
+$info   = site_info($pdo);
+$navbar = site_navbar();
+$current_uri_2 = $current_uri_2 ?? '';
+$GLOBALS['_view_shared'] = compact('info', 'navbar', 'current_uri_2');
+
+echo view('include'); // renders view('seo') inside <head>
+echo view('navbar');
+echo view('messenger_chat');